Green’s Dictionary of Slang

1. fashionable, stylish.

1714		A. Smith Lives of Most Noted Highway-men, etc. I 131: By those killing Features of your charming Face, give a Gentleman leave [...] to say, he’s your humble Servant.
1760		O. Goldsmith ‘A Reverie at the Boar’s-head-tavern, Eastcheap’ Coll. Works (1966) III 102: Your modern Briton cuts his hair on the crown, and plaisters it with hogs-lard and flour; and this to make him look killing.
1771		Smollett Humphrey Clinker (1925) I 54: God knows what havoc I shall make among the mail sex, when I make my first appearance in this killing collar.
1802		T. Dibdin ‘Miss Levi, Miss Rachael and Miss Moses’ [song] She was all over so charming and lovely and killing / she cut ma heart in two all de vorld so it wash a bad Shilling.
c.1813		‘Captain Mulligan’ Wellington’s Laurels 4: Quite an Adonis was Captain Mulligan; / He was willing, She was killing.
1832		Egan Bk of Sports 137: In beauty none could them surpass, / In mansion nor in villa: / For Sal was quite a killing lass, / And Bill was quite a killer.
1840		T. Hood ‘Miss Kilmansegg & Her Precious Leg’ in Poems (1846) I 161: The crowd including two butchers in blue (The regular killing Whitechapel hue).
1856		G.J. Whyte-Melville Kate Coventry (1865) 146: ‘Is that killing ‘get-up’ entirely for our benefit, John?’ I asked. [Ibid.] 15: Her hair done in two such killing plaits.
1866		R. Hallam Wadsley Jack 56: My twoathry wiskers bein varry streight raither bother’d me, havin’ seen a chap wi’ curly uns which gi’d him a varry killin’ appearance.
1879		C.J. Kickham Knocknagow 603: She resolved to make herself as ‘killing’ as possible.
1881		Bulletin (Sydney) 15 Jan. 9/2: I wonder what his poor father, who screwed and saved money as a small watchmaker in Aberdeen, would have said of this ‘killing’ descendent of his, who cannot even lisp distinctly.
1895		C. Crowe Aus. Sl. Dict. 41: Killing, fascinating.
1903		A. Adams Log Of A Cowboy 385: Priest and myself [...] strolled out again and met others of our outfit in the street, scarcely recognizable in their killing rigs.
1910		Bulletin (Sydney) 15 Dec. 36: Billum’s male friends rather cut him for a vain popinjay, though the ladies thought the doctor with his new style of head-dress just too killing.
1917		Bisbee Dly Advertiser (AZ) 25 Mar. 5/5: A Dutch dance was next [...] with killing costumes.
1939		Afro-American (Baltimore, MD) 7 Jan. 9/4: Mex resolved to stop getting those killing haircuts.
1988		(con. 1940s) C. Bram Hold Tight (1990) 186: He [...] walked his coolest, most killing walk toward Hank.

2. (orig. US) fascinating, very interesting, wonderful.

1840		T. Hood ‘Miss Kilmansegg and Her Precious Leg’ in Poetical Wks (1854) 278: For amongst his other killing parts, / He had broken a brace of female hearts.
1844		Commercial Advertiser (N.Y.) 2 Jan. n.p.: There was a pleasant, playful breeze that sported with the well curled locks of first-water dandies [on New Years Day], and gave them a certain négligé appearance, which must have been really killing ’in my lady’s chamber or drawing-room.’.
1866		H.L. Williams Gay Life in N.Y. 92: ‘My what nice eyes you’ve got, ain’t you?’ said the fair waitress with an ogle and a leer which had proved ‘killing’ before on more than one young man.
1873		Sl. Dict.
1884		R.C. Hartranft Journal of Solomon Sidesplitter 105: ‘Don’t you think my eyes look quite killing this morning?’ said a dandy to a smart girl.
1889		Dead Bird (Sydney) 19 Oct. 1/1: Killing fellows — Some of our so-called doctors.
1896		W.C. Gore Student Sl. in Cohen (1997) 17: killing a. Admirable, fascinating.
1899		Crissie 72: ‘I’ve got the most killing little tart on hand for you just now’.
1908		H. Green Maison De Shine 129: I saw the Rossow Midgets, an’ they was too killin’.
1920		Ade Hand-made Fables 241: The Women would insist on having Orlando brought up to the House sometime, because they knew he must be Killing.
1933		Z.N. Hurston Gilded Six-Bits (1995) 989: He say, ‘Ah have to hand it to you, Joe. Dat wife of yours is jes’ thirty-eight and two, Yes-suh, she’s forte!’ Ain’t he killin’?

3. extremely funny.

1853		Dickens ‘Slang’ in Household Words 24 Sept. 76/2: The comic actor last night was ‘killing.’.
1874		L. Troubridge Life amongst Troubridges (1966) 83: She was in her dressing-gown and looked too killing.
1899		Ade Fables in Sl. (1902) 199: The clever Man of the World, who says all the Killing things, is almost as Funny as Ally Sloper.
1907		Marvel 2 Feb. 47: It’s enough to make a cat laugh! Rob, you’re too killing!
1917		E. Pound letter 25 Sept. in Read Letters to James Joyce (1968) 127: Gosse has written a killing letter, professing his willingness to help [...] I can hear Gosse’s snuffy voice sniffing the syllables.
1922		S. Lewis Babbitt (1974) 93: There was a great deal of laughter. Mrs. Jones asserted, ‘Mr. Frink is simply too killing!’.
1959		H.E. Bates A Breath of French Air (1985) 170: ‘Scream,’ Angela Snow said. ‘Killing.’.
1962		P. Crump Burn, Killer, Burn! 97: ‘The killing part is, I crawled all the way.’ Everybody laughed.
1982		Barr & York Sloane Ranger Hbk 158: killing adj. Funny (older Sloanes).