lonely, adj. — Green’s Dictionary of Slang

lonely adj.

SE in slang uses

In compounds

lonely art (n.) [apart from its obvious connotations, note the pun on ‘lonely heart’]

masturbation.

1994

N.Y. Rev. of Books 7 Apr. 🌐 In his new novel, Nicholson Baker turns his full attention to the lonely art, the art of masturbation.

lonelyhearts (n.) (US prison)

men who write letters to female inmates.

1992

Bentley & Corbett Prison Sl. 38: Lonely Hearts Lonely men who correspond with women in prison. In contrast to ‘sponsors,’ lonely hearts rarely send money or gifts.

In phrases

lonely as a bastard on Father’s Day (adj.)

(Aus.) extremely lonely.

1963–74		B. Humphries Barry McKenzie [comic strip] in Complete Barry McKenzie (1988) 93: I sit around on me bum as lonely as a bastard on Father’s day.
2000		R. Schaap on squawk.ca 30 Aug. 🌐 Being a leftie hurts, I reckon. [...] Lonely as a bastard on Father’s Day, for a start.

lonely in the weather (n.) [their head is ‘in the clouds’]

(W.I.) a tall, thin person.

1958

cited in Cassidy & LePage Dict. Jam. Eng. (1980).

on one’s lonely (also by one’s lonely, for one’s..., on one’s lone)

by oneself.

1895		E. Townsend Chimmie Fadden Explains 50: De nurse tinks dat dat gives her de house to own all for her lonely.
1901		J. Flynt World of Graft 66: If they don’t, they’re in a class by their lonelies, ’cause everybody rubbers in this town.
1906		Gadfly (Adelaide) 25 Apr. 6/1: Well, this ’ere Sue made up ’er mind – / She fair made up her mind – / She’d wander on ’er lonely down to town, / All on ’er own, that is, alone.
1910		Bulletin (Sydney) 18 Aug. 13/2: ‘If it’s not in a pub you’re on your lonely,’ he replied.
1912		J. London Smoke Bellew Pt 12 🌐 He knows a way out – learned it on huntin’ trips – to the west of the way you an’ me came. He ain’t had the nerve to tackle it by his lonely.
1936		T. O’Reilly Tiger of the Legion 92: ‘Say, Tiger, don’t you go, neither! [...] Don’t leave your old mate on his lone in this rotten hole!’.