Green’s Dictionary of Slang

1. eccentric, whimsical.

1683		W. Kennett (trans.) Erasmus Witt against Wisdom (1509) 148: [A] man is censured at least for being maggoty, and crack-braind.
1696		Motteux (trans.) Pantagruelian Prognostications (1927) II 695: Those who belong to Madam Luna [...] lunatics, maggoty fools, crack-brained coxcombs.
1706		Farquhar Recruiting Officer II ii: I should have some rogue of a builder [...] to adorn some maggotty, new-fashioned bauble upon the Thames.
1710		C. Shadwell Fair Quaker of Deal II i: I am in a very Maggotty Humour.
1725		New Canting Dict. n.p.: Whimsical, maggotish.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1794		W. Godwin Caleb Williams (1966) 122: If we little folks had but the wit to do for ourselves, the great folks would not be such maggotty changelings as they are.
1811		Lex. Balatronicum.
1817–26		Kirby & Spence Introduction to Entomology 85: the common saying that a whimsical person is maggotty, or has got maggots in his head, perhaps arose from the freaks sheep have been observed to exhibit when infested by bots [F&H].
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1860		Hotten Dict. of Modern Sl. etc. (2nd edn) 172: MAGGOTY, fanciful, fidgetty. Whims and fancies were formerly termed maggots, from the popular belief that a maggot in the brain was the cause of any odd notion or caprice a person might exhibit.
1870		Hotten Sl. Dict. [as cit. 1860].
1873		Sl. Dict.

2. (US/Irish, also maggot) extremely drunk.

1906		Salt Lake City (UT) 30 Mar. 4/5: He is [...] scammered, maggoty, sewed-up .
1922		DN V 336: Maggoty [...] drunk.
1935		(con. 1920s) J.T. Farrell Judgement Day in Studs Lonigan (1936) 471: I was maggoty drunk.
c.1940–5		‘Myles na gCopaleen’ Best of Myles (1968) 338: Drunk; jarred; [...] mouldy; maggoty; full to the brim.
1941		C.R. Bond 22 Nov. in A Flying Tiger’s Diary (1984) 47: Smith, equally magotty, was with him.
1973		H. Leonard Da (1981) Act II: But no, you couldn’t wait to get maggoty drunk.
1974		Star Press (Muncie, IN) 24 Oct. 23/2: The Irish have at least two dozen words for inebriation [...] killarneyed, fluthered, stotious, pallatic, maggoty, blithero, half-tore, paralytic and stoven.
1981		P. Crosbie Your Dinner’s Poured Out! 23: It was common local knowledge that Edward VII [...] was found ‘maggoty mouldy’ drunk in O’Connell Street by an innocent policeman.
1986		(con. 1930s) P. O’Farrell Tell me, Sean O’Farrell 78: The Clane man got maggoty, mouldy, eejity and struck the earl with the red cap.
1994		(con. 1920s–30s) K.C. Kearns Dublin Tenement Life 213: Everyone would get their beer and came home mouldy, maggoty drunk!
2003		Aus. Word Map n.p.: maggot […]Another word for really drunk, or under the influence of excessive alcohol: ‘Chris was really maggot last night’.
2007		D. Szalay London and the South East 227: She was usually tipsy when she got home; sometimes maggoty.
2016		Voat 13 Oct. 🌐 ‘Check out old mate over, there he’s fuckin maggot’.

3. (Aus.) ill-tempered, irritable.

1919		W.H. Downing Digger Dialects 33: maggoty — Angry.
1924		(con. WWI) A.G. Pretty Gloss. Sl. [...] in the A.I.F. 1921–1924 (rev. t/s) n.p.: maggotty. Angry.
1940		F. Sargeson ‘I’ve Lost My Pal’ in A Man And His Wife (1944) 47: Sometimes he’d go maggoty because one of the dogs would start barking. He said it got on his nerves.
1951		D. Stivens Jimmy Brockett 31: My old man made me maggotty by asking me one day, ‘Do you shave up or down?’ ‘Down,’ I said. ‘Just what I thought,’ the old man said.
1968		S. Gore Holy Smoke 91: Like them kind that’s always goin’ maggoty on yer.
1996		B. Scott Banshee and Bullocky 100: Scotty got a bit maggoty about this.
2003		McGill Reed Dict. of N.Z. Sl. 131: maggoty Unwell or irritable. ANZ c.1915.

4. (Irish/US) dirty, disgusting.

1930		J.T. Farrell ‘Well, That’s That’ in Short Stories (1937) 260: The bums are pretty maggoty, but a jane is a jane, and for the grand old purpose, they’re all the same.
1957		M. Shulman Rally Round the Flag, Boys! (1959) 97: Lousy, maggoty civilians.
1966		P. Boyle At Night All Cats Are Grey 251: God blast yer maggoty sowl, are ye gone mad?
1972		B. Hannah Geronimo Rex 193: These white walls [...] were looking too much like a hospital for sanctimonious one-eyed fuckers, and for all the rest of you maggoty little finks.
1989		K. Dunn Geek Love 131: We’re gonna shove that maggoty goat back into the ittle trailer!
1993		(con. 1930s) M. Verdon Shawlies, Echo Boys, the Marsh and the Lanes 23: ‘You maggoty-looking article,’ he told the saint.