Green’s Dictionary of Slang

1. used as an affirmative at the end of a statement, isn’t it/he/etc, e.g. That’s a nasty fellow, what?

1567		R. Edwards Damon and Pithias (1571) Fi: Away you cracke ropes, are you fighting at the Courte gate? [...] I wyll swindge you both, what?
1687		C. Sedley Bellamira I i: Did I say such bug-words [...] ’Twas when I was in my Altitudes, what?
1854		G.J. Whyte-Melville General Bounce (1891) 117: Don’t like your politics, what? never did.
1884		Sporting Times 20 Dec. 5/4: ‘What Babykins! this is ripping [...] Have a drink?’.
1899		E.W. Hornung Amateur Cracksman (1992) 9: You’re a nice chap, Bunny! A real desperate character – what?
1901		A. Binstead More Gal’s Gossip 140: We get a surfeit of dog-meat here; but it looked plump, and I’m told they enjoyed it in the kitchen. What?
1912		Conan Doyle Lost World 81: ‘Mr. Malone, I understand,’ said he. ‘We are to be companions - what?’.
1915		H.L. Wilson Ruggles of Red Gap (1917) 331: No end of a spree, what, what!
1922		Joyce Ulysses 102: Everything went off A 1, he said. What?
1933		M. Marshall Tramp-Royal on the Toby 30: So now to roll a fag [...] Better than Havanas, what?
1942		A. Christie Body in the Library (1959) 48: Created a bit of a stir in the neighbouhood – what?
1956		J. Curtis Look Long Upon a Monkey 69: Is that half-section of yours being bloody-minded, what?
1961		‘Frank Richards’ Billy Bunter at Butlins 99: ‘Rolling in it, what?’ asked Johnny Bull, sarcastically.
1978		F. Norman Dead Butler Caper 9: Extremely sensible, what?
1986		S. King It (1987) 884: Sing old Elvis Presley songs? What?

2. short for What did you say? or What is it?

1675		C. Cotton Scoffer Scoff’d (1765) 254: What! Is the fellow a mere Bumpkin, / A down-right Clod.
1751		Smollett Peregrine Pickle (1964) 252: What! (cried the painter in despair) part with my manhood, and become a singer?

3. (also eh, what?) an expletive tacked on to the end of a sentence to give it greater emphasis but of no actual meaning.

1850		‘Ned Buntline’ G’hals of N.Y. 69: As for him, won’t I spill some of his shiners? W-h-a-t!
1910		Wodehouse Gentleman of Leisure Ch. xxv: ‘I say, you know, what ho!’ he observed, not without emotion. ‘What?’.
1914		C. Holme Lonely Plough (1931) 156: Just the night for ‘Everybody’s Doing it’ – what?
1922		Joyce Ulysses 562: Sure they wanted me to join with the mots. No, by God, says I. Not for old stagers like myself and yourself. [...] Thanks be to God we have it in the house what, eh, do you follow me?
1923		Wodehouse Inimitable Jeeves 43: Well, I mean to say, what!
1926		‘Ford Madox Ford’ Man Could Stand Up 130: The genial, rubicund, slightly whiskified C.O. who finishes every sentence with the words: ‘Eh, what?’.
1927		Chillicothe (MO) Constitution 17 Jan. 3/4: [headline] Bally Amerian [sic] Slang A Bit Thick. Eh, What?
1939		K. Tennant Foveaux 22: Do I bloody well wot!
1956		K. Amis letter 24 Sept. in Leader (2000) 480: I have been a bit of an old fool, getting tied up with a young woman here, not to say really tied up, just started fucking her what.
1960		Wodehouse Jeeves in the Offing 30: Fellows who had more or less shot their bolt after saying ‘Eh, what?’.
1977		G. Melly Rum, Bum and Concertina (1978) 120: I say old boy, what, what.
1987		S. King Misery (1988) 155: Griquas. Wonderful chaps. Put sticks and things in their smoochers, what?
2006		G. Iles Turning Angel 164: Ellen told me I should go along, that it’s the kind of real-world experience that a lot of kids [...] may already have had. I mean, what?