From the second edition (1989):
monster, n. and a.
(ˈmɒnstə(r)) Forms: 3–6 monstre, 5–6 Sc. monstir, -tour, 6 mounster, monstur(e, -tuire, Sc. -toure, 5– monster. [OF. monstre (= Pg., It. monstro), ad. L. monstrum monster, something marvellous; orig. a divine portent or warning, f. root of monēre to warn.]

A. n.

1. Something extraordinary or unnatural; a prodigy, a marvel. Obs.

c1374 Chaucer Boeth. ii. pr. i. 20 (Camb. MS.) Thilke meruayles Monstre [L. illius prodigii] fortune. 1382 Wyclif 2 Macc. v. 4 Alle men preyeden, the monstris, or wondres,‥for to be turned in to good. c1412 Hoccleve De Reg. Princ. 344 Was it not eek a monstre as in nature þat god I-borë was of a virgine? c1430 Lydg. Min. Poems (Percy Soc.) 119 It were a monstre geyne nature, as I fynde, That a grete mastyfe shuld a lyoun bynde. 1533 Bellenden Livy iv. viii. (S.T.S.) II. 74 Is it nocht ane huge monstoure,‥þat It [sc. the city] suld haue made him king. 1537 in Lett. Suppress. Monast. (Camden) 160 The vicar off Mendyllsham‥hath‥brought home hys woman and chyldern into hys vicarage. Thys acte by hym done is in thys countre a monster, and many do growge at it. 1558 Knox First Blast (Arb.) 20 He that iudgeth it a monstre in nature, that a woman shall exercise weapons. 1562 Winȝet Last Blast Wks. (S.T.S.) I. 44 Ingratitude and vtheris deuyllische monstres of vice. 1614 Budden tr. Ærodius' Disc. Parents' Hon. (1616) 5 Contempt, impiety, murdering of parents, were therefore ordinary monsters among the Greekes. 1641 Vind. Smectymnuus vii. 91 That power, which was a stranger and a monster to former times. 1702 Eng. Theophrast. 43 'Tis the rarity that makes the monster. 1710 Shaftesbury Adv. Author iii. iii. 183 Monsters and Monster-Lands were never more in request.

2. a. An animal or plant deviating in one or more of its parts from the normal type; spec., an animal afflicted with some congenital malformation; a misshapen birth, an abortion. Cf. monstrosity.

a1300 Cursor M. 9846 If þou fand‥A barn‥þat had thre fete and handes thre, And if þou siþen a-noiþer fand þat wanted oiþer fote or hand,‥monstres moght man call þam like. c1400 Mandeville (1839) v. 47 A monstre is a thing difformed aȝen Kynde both of Man or of Best. 1481 Caxton Myrr. i. xiv. 44 Or it hath a membre lasse than he ought to haue,‥and may be called therfor a monstre. 1556 Chron. Gr. Friars (Camden) 57 A monstre, a calfe wyth ij. heddes, iiij. eres, iiij. eyne, viij. f[eete] and ij. taylles. 1607 Topsell Four-f. Beasts 337 A horsse-keeper which broght‥an infant, or rather a monster, which he had got vpon a Mare. 1614 B. Jonson Bart. Fair iii. i, Then you met the man with the monsters, and I could not get you from him. a1680 Butler Rem. (1759) II. 72 His Parts are disproportionate to the whole, and like a Monster he has more of some, and less of others than he should have. 1717 Lady M. W. Montagu Let. to C'tess Mar 16 Jan., The princes keep favourite dwarfs. The Emperor and Empress have two of these little Monsters. 1727–41 Chambers Cycl. s.v. Mule, Mules, among gardeners, denote a sort of vegetable monsters. 1754–64 Smellie Midwif. I. 123 When two children are distinct they are called twins; and monsters, when they are joined together. a1793 J. Hunter Ess. & Observ. (1861) I. 240 The vegetable kingdom abounds with monsters. 1840 Poe 1002nd Tale Wks. 1864 I. 141 The term ‘monster’ is equally applicable to small abnormal things and to great. 1897 Allbutt's Syst. Med. IV. 528 It [i.e. congenital absence of spleen] has been noted in monsters.

b. transf. and fig.

1604 Shakes. Oth. iii. iii. 107 Thou ecchos't me; As if there were some Monster in thy thought Too hideous to be shewne. 1821 Scott Kenilw. xxx, Varney was one of the few—the very few moral monsters, who contrive to lull to sleep the remorse of their own bosoms. 1837 Emerson Address, Amer. Schol. Wks. (Bohn) II. 175 The state of society is one in which the members have suffered amputation from the trunk, and strut about so many walking monsters. 1873 M. Arnold Lit. & Dogma (1876) 356 The non-Christian religions are not to the wise man mere monsters.

3. a. An imaginary animal (such as the centaur, sphinx, minotaur, or the heraldic griffin, wyvern, etc.) having a form either partly brute and partly human, or compounded of elements from two or more animal forms.
Except in heraldic use, the word usually suggests the additional notion of great size and ferocity, being specifically associated with the ‘monsters’ victoriously encountered by various mythical heroes.

c1385 Chaucer L.G.W. 1928 (Ariadne) This Minos hath a monstre, a wikked beste, That was so cruel that‥he wolde him [i.e. a man] ete. 1390 Gower Conf. III. 123 A Monstre [i.e. Sagittarius] with a bowe on honde: On whom that sondri sterres stonde. c1420 Pallad. on Husb. i. 935 For eddris, spritis, monstris, thyng of drede. To make a smoke and stynk is good in dede. 1490 Caxton Eneydos xv. 58 Wherof was made a monstre fulle terrible, that hath as many eyen in her hede‥as she hathe fedders vpon her. 1500–20 Dunbar Poems xxxv. 28 He sall ascend as ane horrebble grephoun, Him meit sall in the air ane scho dragoun; Thir terrible monsteris sall togidder thrist. 1567 Gude & Godlie Ball. (S.T.S.) 214 Thocht Hercules, for Exionie, A mychtie monster did subdew, Zit endit he in miserie. 1586 Marlowe 1st Pt. Tamburl. iv. iii, A monster of fiue hundred thousand heades, Compact of Rapine, Pyracie, and spoile. 1610 Shakes. Temp. ii. ii. 69 This is some Monster of the Isle, with foure legs. 1613 Purchas Pilgrimage (1614) 54 Annedotus a Monster (otherwhere like a fish, his head, feet and hands like a Man). 1737 Pope Hor. Epist. ii. i. 18 The great Alcides, ev'ry Labour past, Had still this Monster [sc. Death] to subdue at last. 1821 Byron Sardan. i. ii, A sort of semi-glorious human monster. 1874 Papworth & Morant Brit. Armorials Introd. 7 How difficult it often is to determine what species of beast, bird,‥monster,‥or tree, a charge was intended to represent. 1875 Jowett Plato (ed. 2) V. 13 The book of the Laws if left incomplete is compared to a monster wandering about without a head. 1893 Cussans Her. (ed. 4) 98 The Dragon is a winged monster.

b. transf. and fig.

1500–20 Dunbar Poems xxvi. 91 The fowll monstir Glutteny. 1515 Barclay Egloges iv. (1570) Cvjb, Fearefull is labour,‥Dreadfull of visage, a monster intreatable. 1560 J. Daus tr. Sleidane's Comm. 17b, He would wishe that all learned men woulde set on with touch and nayle to overcome that Monstre. 1666 Dryden Ann. Mirab. ccxviii, The infant monster [i.e. the fire of London], with devouring strong, Walk'd boldly upright with exalted head. 1702 Rowe Tamerl. i. i. 96 Oh thou fell Monster, War. 1825 Lytton Zicci i, The monster that lives and dies in a drop of water—carnivorous—insatiable. 1856 Emerson Eng. Traits, Wealth Wks. (Bohn) II. 75 Engineers and firemen without number have been sacrificed in learning to tame and guide the monster [sc. Steam].

¶In collocations like ‘faultless monster’, ‘monster of perfection’, connoting an incredible or repulsively unnatural degree of excellence.

1682 Sheffield (Dk. Buckhm.) Ess. Poetry 235 Reject that vulgar error which appears So fair, of making perfect characters, There's no such thing in Nature, and you'l draw A faultless Monster which the world ne're saw.

4. A person of inhuman and horrible cruelty or wickedness; a monstrous example of (wickedness, or some particular vice).

1556 J. Heywood Spider & F. liv. 22 Which deede: if we do, wheare are our like monsturs? 1598 B. Jonson Ev. Man in Hum. iii. iii, And he to turne monster of ingratitude, and strike his lawfull host. 1605 Shakes. Lear i. ii. 102 He cannot bee such a Monster. 1613 Purchas Pilgrimage (1614) 51 That Monster of irreligion, Mahomet. 1642 D. Rogers Naaman 14 Open monsters and odious livers. 1683 Evelyn Diary 5 Dec., That monster of a man, Lord Howard of Escrick. 1707 Watts Hymns & Spir. Songs i. xxxix. (1751) 28 Should Nature change, And Mothers Monsters prove. 1713 Addison Guard. No. 105 ⁋5 These monsters of inhumanity. a1715 Burnet Own Time ii. (1724) I. 269 Dryden‥being a monster of immodesty. 1783 Justamond tr. Raynal's Hist. Indies VI. 293 They were no sooner landed at Barbadoes, but the monster sold her who had saved his life. 1847 Emerson Repr. Men, Montaigne Wks. (Bohn) I. 336 The correspondence of Pope and Swift describes mankind around them as monsters. 1877 Mrs. Oliphant Makers Flor. xii. 297 Alexander VI was a monster of iniquity. 1887 Bowen Æneid i. 347 Pygmalion, monster unrivalled in hellish deed.

5. An animal of huge size; hence, anything of vast and unwieldy proportions.

1530 Palsgr. 744/2 A monster of the see. a1533 Ld. Berners Huon I. 167, I condempne thee to be .xxviii. yeres a monster in ye see. 1613 Purchas Pilgrimage (1614) 839 A great beast‥(a Crocodile or some other monster). 1738 Wesley Ps. cxlvii. vii, Monsters sporting on the Flood, In scaly Silver shine. 1759 Goldsm. Polite Learn. (Globe) 432/2 From these inauspicious combinations proceed those monsters of learning, the Trevoux, Encyclopédies, and Bibliothèques of the age. 1832 Tennyson Lotos-eaters 152 The wallowing monster spouted his foam-fountains in the sea. 1966 K. Martin Father Figures i. 20 Buying from the all-purposes shop bullseyes and, for a penny, ‘monsters’, which were big bottles of fizzy lemonade.

6. attrib. and Comb. a. simple attrib., as monster-brood, monster-bulk, monster-land, monster-market, monster-spite; monster-like adj. and adv.; monster-browed, monster-headed adjs.; b. objective, as monster-master, monster-monger, monster-queller, monster-slayer, monster-tamer; monster-bearing, monster-breeding, monster-killing, monster-quelling, monster-slaying, monster-taming, monster-teeming adjs.; c. instrumental, as monster-guarded, monster-spouted adjs.; d. appositive, as monster-cloud, monster-crew, monster-god, monster-lord, monster-machine, monster-man, monster-mask, monster-master, monster-paddock, monster-people.

1648 Fanshawe Il Pastor Fido i. v. 9 The *monster-bearing earth Did never teem such a prodigious birth. 1728 Pope Dunc. i. 108 In each she marks her Image full exprest, But chief, in Tibbalds *monster-breeding breast. 1738 Gray Propertius ii. 41 Earth's *monster-brood stretch'd on their iron-bed. 1929 Blunden Near & Far 49 Though the full cloud Frowns *monster-browed. 1697 Dryden Æneid ix. 959 Down sunk the *Monster-Bulk, and press'd the Ground. 1934 Blunden Mind's Eye 16 A sky of freakish *monster-clouds. 1697 Dryden Æneid viii. 395 Thy Hands, unconquer'd Heroe, cou'd subdue The Cloud~born Centaurs, and the *Monster Crew. 1716 Pope Iliad v. 954 To tame the *Monster-God Minerva knows, And oft' afflicts his Brutal Breast with Woes. 1594 Selimus K2, Thou hast trode The *monster-garded [printed monster-garden] paths, that lead to crownes. 1869 ‘Mark Twain’ Innoc. Abr. xx. 147 The more immediate scenery consisted of fields and farm-houses outside the car, and a *monster-headed dwarf and a moustached woman inside it. These latter were not show-people. 1966 English Studies XLVII. 141 Digressions‥thrown in by the poet‥as the fair means by which an experienced teller of long stories overcomes the monotony of a series of *monster-killings. 1710 Shaftesbury Adv. Author iii. iii. 183 Monsters and *Monster-Lands were never more in request. 1736 Thomson Liberty v. 676 Vanish'd Monster-land. 1561 T. Norton Calvin's Inst. iii. xxii. (1634) 456 It was a *monsterlike change that the honour of first birth was removed to Jacob. 1606 Shakes. Ant. & Cl. iv. xii. 36 Monster-like. 1610 J. Guillim Her. iii. xxvi. 183 Animals, which being duly shaped, doe neuerthelesse monster-like degenerate from their kind. 1655 H. L'Estrange Chas. I, 119 In the same moneth‥wherein this *Monster-Lord [Audley] was sentenced. 1970 G. Jackson Let. 4 Apr. in Soledad Brother (1971) 211 He was giving to us all of the life force and activity that the *monster-machine had left to him. 1598 Sylvester Du Bartas ii. i. ii. Imposture 638 Which, like the vaunting *Monster-man of Gath, Have stirr'd against us little David's wrath. 1690 Dryden Amphitryon v. i, Monsters and monster men he shall engage. 1638 Junius Paint. Ancients 43 A man may find them always upon the *monster-market, where they stand and stare upon such maimed creatures. 1969 L. J. Chiaramonte in Halpert & Story Christmas Mumming in Newfoundland 89 They are great favourites with little children, who beg their parents for money to buy a new *monster mask. 1598 Sylvester Du Bartas ii. ii. ii. Babylon 85 This *monster-master stout, This Hercules‥they tender. 1634 Sir T. Herbert Trav. 5 Guiding their Monster-masters to a prey. 1704 Swift T. Tub v, I have always looked upon it as a high Point of Indiscretion in *Monster-mongers, and other Retailers of strange Sights, to hang out a fair large Picture over the Door, drawn after the Life. 1634 Massinger Very Woman iii. i, A March Frog kept thy mother; Thou art but a *monster Paddock. 1680 Otway Caius Marius i. i, The *Monster-people roar'd aloud for joy. 1751 Pope's Dunciad iv. 492 Scribl. note, It becomes a doubt, which of the two Hercules's was the *Monster-queller. 1959 A. G. Brodeur Art of Beowulf 81 Outside the climate of mutual love‥, Beowulf would be little more than the monster-queller and marvelous swimmer of folk-tale. 1948 K. Malone in English Studies XXIX. 167 Beowulf's mention of sea-monsters‥takes us back to the swimming match with Breca, one detail of which is precisely this monster-quelling on the part of the hero. 1948 L. Spitzer Linguistics & Literary Hist. iii. 98 She must ask Hippolyte to resemble his father, the *monster-slayer, by slaying the monster that she has become. Ibid. 95 We learn that Hippolyte has not, to his regret, equaled his father in his feats of *monster-slaying. 1797 College 26 How to mitigate their *monster-spite. 1942 Blunden Romantic Poetry & Fine Arts 17 *Monster-spouted fountain. ?1606 Drayton Eglog iv. Poems D7b, Such *monster-tamers who would take in hand? 1648 Fanshawe Il Pastor Fido i. i. 155 That *monster-taming King‥Had never grown so valiant‥If first the monster Love he had not tam'd. 1819 Shelley Prometh. Unb. i. 447 Never yet there came Phantasms so foul through *monster-teeming Hell.

7. Special Comb., as †monster-little-man, a dwarf monstrosity; †monster-love, a deformed or aborted love.

1607 Topsell Four-f. Beasts 12 The most parte thought him to be some Monster-little-man. 1633 Ford Broken H. i. i, This thought Begets a kind of monster-love.

B. adj. [developed from the attrib. and appositive use of the n.]

1. Of extraordinary size or extent; gigantic, huge, monstrous. Cf. monstre a.

1837 (title of play) The elements—earth, air, fire water; or, The monster ballroom of 1837 (R.A.M. 15/5/1837). 1839 Spirit Metrop. Conserv. Press (1840) II. 152 This monster product of our time. c1842 F. Rogers (Ld. Blachford) Lett. (1896) 113 The phrase ‘monster meeting’ was due to me. An immense balloon‥had been popularly christened the ‘monster balloon’, and I applied the phrase contumeliously to one of O'Connell's immense‥meetings. 1843 Borrow Bible in Spain xxxvi, The monster bell of Moscow. 1843 Ann. Reg. 227 The assemblage of immense masses of people‥denominated ‘Monster Meetings’. 1844 Lingard Anglo-Sax. Ch. (1858) II. App. C. 344 In the old church‥was a monster organ. 1853 Kane Grinnell Exp. xlvi. (1856) 423 The port of Pröven is securely sheltered by its monster hills. 1868 Disraeli Let. to Mrq. Abercorn 8 June in Davey's Catal. (1895) 21, I have to receive this morning a monster deputation of your Excellency's subjects. 1901 Oxford Times 16 Mar. 4/2 This monster liner, will‥be the biggest vessel afloat. 1952 ‘R. Crompton’ William & Tramp ii. 83 Their jaws never ceased to move rhythmically around a couple of Monster Humbugs. 1961 Guardian 27 Sept. 8/3 Many older housewives‥find great satisfaction in a monster weekly ‘bake’.

2. Comb. with advb. force = ‘like a monster’, as monster†-eating, monster-neighing adjs. rare.

1607 Topsell Four-f. Beasts 261 Their‥liuely vgly figure, represented in this monster-eating-beast. 1886 Kipling Departm. Ditties, etc. (1888) 82 An incarnation of the local God, Mounted upon a monster-neighing horse.

Hence †ˈmonsterful a., marvellous, extraordinary. †ˈmonsterfy v., to make monstrous. ˈmonsterhood, the state of being a monster. ˈmonstership, a mock title for a monster.

c1400 Beryn 2767 These monstrefulle thingis, I devise to the Be-cause þow shuldist nat of hem a-basshid be. 1597 Warner Syrinx Niv, These Monsters [abusers of women] woulde monsterfie the Manners and beautifull Ornaments of Women. 1598 B. Jonson Ev. Man in Hum. iii. ii, Let who will make hungrie meales for your monster-ship, it shall not bee I. a1745 Swift Dr. Delany's Reply 10 'Tis so strange, that your monstership's crany Should be envied by him, much less by Delany. 1852 Fraser's Mag. XLV. 90 It was a Behemoth of puffs‥standing alone in solitary monsterhood.