Green’s Dictionary of Slang

half-assed adj.

also half-arse, half-arsed, half-ass
[SE half + ass n. (2)/arse n. (1)]
(orig. US)

careless, inadequate, incompetent, second-rate.

Northern Whig (Hudson, NY) 5 Apr. 3/4: Having arrived with his Phalanx opposite the house of a certain gentleman, he ordered them to halt, and then addressed them — ‘Republicans! I have got so hoarse I cannot halloo -- you must cry out -- “C********** H****! *the half-arsed tory! -- Huzza!*”’ -- which was three times repeated by his ‘*republican*’ companions, to the great mirth and amusement of a crowd of negro wenches, which by this time had joined their standard.
[US] in T.P. Lowry Stories the Soldiers Wouldn’t Tell (1994) ) 47: There goes our half-assed Adjutant.
[US]J.L. Kuethe ‘Johns Hopkins Jargon’ in AS VII:5 333: half-assed—mediocre; insignificant.
[US]V.F. Nelson Prison Days and Nights 25: They [...] let us have three half-arse meals a day and a cell to sleep in at night.
[US](con. 1944) J.H. Burns Gallery (1948) 87: Only the half-arsed poets invented love as a force that has nothing to do with anything.
[US]H. Miller Sexus (1969) 134: Only a half-assed painter would deny the value of Cezanne’s work.
[US]J. Jones From Here to Eternity (1998) 431: ‘What is pseudo?’ Prewitt asked. ‘It means half-assed,’ Angelo said. [Ibid.] 886: But a half-assed fool couldnt do it, any more than a half-assed fool could do anything, and do it well.
[US]T. Williams Cat on a Hot Tin Roof Act II: big daddy: That half-ass story! brick: What’s half-ass about it?
[Ire](con. 1940s) B. Behan Borstal Boy 99: Such a half-arsed class of story I never heard.
[US](con. 1940s) G. Mandel Wax Boom 286: The Krauts [...] wouldn’t have budged toward that mountain with the half-ass strength they had.
[US]P. Highsmith Two Faces of January (1988) 226: He wasn’t going to be a pushover for Rydal Keener, that spineless vagabond, that half-assed soldier of fortune.
[UK]T. Keyes All Night Stand 189: ‘I haven’t got the bread.’ [...] ‘Course you have, you half-arsed git.’.
[US]V.E. Smith Jones Men 161: You’re trying to screw me out of a good thing [...] with your half-ass way of doing shit.
[US]A. Maupin Tales of the City (1984) 187: What the hell does she need with some half-assed lover who’s got the hots for tile bathrooms.
[Aus]D. Maitland Breaking Out 125: A little half-arsed cattle town.
[US]A.K. Shulman On the Stroll 151: If you lose your nerve and get ready to blow after your first little half-ass freak, then how’m I ever gonna trust you?
[US]H. Selby Jr Song of the Silent Snow (1988) 11: Danny, a half-assed hustler from 43rd Street.
[UK]T. Blacker Fixx 240: No budget, Daddy’s money, and some half-arsed scheme.
[UK]S. Armitage ‘C.V.’ in Dead Sea Poems 7: Square eyes, half-arse O.U. student.
[UK]N. Cohn Yes We Have No 7: Rather an ardent fascist than a half-arsed liberal.
[UK]Observer Rev. 5 Sept. 8: We did the right thing – OK, in a half-assed sort of way.
[US]P. Beatty Tuff 150: By [...] accepting Inez’s money he’s made a half-ass commitment to his life.
[UK]Guardian Guide 8–14 Jan. 12: A horribly half-arsed storyline.
[US]G. Pelecanos Night Gardener 99: He’d see Asa on the football field, making half-assed tackles.
[US]T. Dorsey Atomic Lobster 70: ‘You have to go back that far?’ ‘I don’t do half-ass history.’.
[Aus]P. Temple Truth 82: Vickery and a cop called Gary Plaice almost killed a half-arsed little robber called Ivanovich.
[UK]J. Fagan Panopticon (2013) 181: Get up, fuck about, have the odd half-arsed meeting.
[US]D. Winslow The Force [ebook] Every half-ass low level dope slinger Torres ever ripped.