Green’s Dictionary of Slang

1. of a human, unstable, unsteady on one’s feet; of an animal, lame.

1870		Sportsman 9 Apr. 4/6: Although he begins to go a little stiff in his limbs and ‘dotty’ on his feet he enjoys good health .
1886		Sporting Times 10 Apr. 2/3: [of a racehorse] Highland Chief [...] also pulled up ‘dotty’.
1888		J. Runciman Chequers 88: I’ll come with you a little way. You’re dotty a bit.
1894		J. Astley Fifty Years (2nd edn) I 157: Arthur [...] is a bit handicapped by going rather dotty on the near fore.
1898		F. Norris Moran of the Lady Letty 281: Shore leave, is it? [...] You’ll come back this time dotty with opium.
1905		Marvel III:63 22: P’r’aps you’d had a bang on the head, sir, and had been struck dotty.
1914		Sport (Adelaide) 17 July 3/4: J.T. [...] is getting very dotty on his feet .
1929		(con. c.1920) J.B. Booth London Town 274: Looks a trifle dotty on his pins.

2. (also dotty in the dome) eccentric, odd; thus dottiness, eccentricity; dotty homestead, dotty house, a pyschiatric institution.

1890		Bulletin (Sydney) 23 Aug. 14/4: What odds to a golden-haired Tottie / Is the loss of a dissolute swain? / If her rival is driving him ‘dotty’ / Miss Tot hasn’t suffered in vain.
1891		Albert Chevalier ‘The Dotty Poet’ 🎵 All competitors he licks now, He’s the dottiest of dotty poets out! [...] Why there never was a dottier than he.
1901		‘Hugh McHugh’ Down the Line 35: ‘Oh! she’s such a happy wappy ’ittle fing!’ giggled the dotty dame.
1906		Sun. Times (Perth) 25 Mar. 4/8: Your dotty old mother / Likes sauce in her stew.
1907		B. Fisher A. Mutt in Blackbeard Compilation (1977) 6: Get wise to yourself. You’re dotty in the dome.
1908		D. Stewart Wild Tribes of London in Illus. Police News 15 Feb. 12/4: ‘[C]uss me if you’re not going dotty, old man!’.
c.1910		H.E. Lee ‘Tough Luck’ Variety Stage Eng. Plays 🌐 I’m so gone on her that I’m the head nominee for the dotty homestead.
1910		Sun. Times (Perth) 6 Mar. 2nd sect. 9/1: They Say [...] That journalistic anxiety concerning the Indian mutiny is driving a pressman dotty.
1912		Day Book (Chicago) 19 Sept. 11/2: Give me a nice cozy little corner in the violent ward of the dotty house.
1915		G. Bronson-Howard God’s Man 197: All these dames are the same when they first hit the bright lights. They go plumb dotty.
1922		Joyce Ulysses 152: Watch him, Mr Bloom said. He always walks outside the lampposts. Watch! – Who is he if it’s a fair question, Mrs Breen asked. Is he dotty?
1922		Gippsland Times (Vic.) 2 Nov. 5/2: A tabbie wot wud pull yew on / Wud wanter be well potty, / Or else she’d be wot they call gone, / A shingle short, or dotty.
1923		R. McAlmon Village 57: His mother was [...] supposed to be half dotty in her German upper storey.
1937		Jennings & Madge May the Twelfth: Mass-Observation Day-Surveys 4:75: And now the Coronation is driving London dotty.
1949		Wodehouse Mating Season 27: One’s deaf, one’s dotty, and they’re all bitches.
1957		P. Larkin letter 5 Jan. in Thwaite Sel. Letters (1992) 272: He isn’t really a fucking commie, is he? I thought he was just dotty.
1962		R. Cook Crust on its Uppers 98: People think that deviation, if it’s not just dotty like in the movies, is dead clever.
1970		H.E. Bates A Little of What You Fancy (1985) 499: Blake was dotty [...] All wonderful people are dotty.
1980		R. Dahl Twits (1982) 75: He’s dotty! [...] He’s balmy!
1989		T. Blacker Fixx 291: Dotty she may have been, but the flair for self-promotion remained.
1999		Indep. Mag. 30 Oct. 37: My dotty uncle who lived in the Borders.
2000		Indep. on Sun. Culture 9 Jan. 2: A gaggle of dotty British expats.
2021		J. Ellroy Widespread Panic 21: Perino’s [...] catered to sterile stiffs and dotty dowagers.
2024		J. Meades Empty Wigs (t/s) 854: [The book] was dotty. It was dangerously deranged. Really loopy.

3. usu. constr. with preps. on/over, in love with, desirous of.

1903		Bulletin (Sydney) 3 Sept. 36/2: Langton was the dottiest of the lot on the girl, so when she asked him to give the poor fellow a job, he said ‘certainly,’ and put him on feeding.
1905		Wash. Post 15 Jan. 4/3: The young man of tender years [...] has a vocabulary which would put Webster to shame [...] Sis is ‘dotty’ over her beau.
1910		Sun. Times (Perth) 12 June 6/5: Heavy encounters with prospectors who have gone dotty on pugilism.
1913		J. London Valley of the Moon (1914) 184: If I get fired, it’ll be his fault. I’m clean dotty over him [i.e. a baby].
1917		G. De S. Wentworth-James Man Market 117: Fancies? Why she’s dotty on him!
1938		N. Lindsay Age Of Consent 81: What about that cigarette tobacco? I’m absolutely dotty for a smoke.
1940		N. Mitford Pigeon Pie 206: Now that’s a man I could have been dotty about.
1971		(con. WWII) B. Aldiss Soldier Erect 101: He’s dotty on them Wog gods, aren’t you Subby, me old oppo?