Green’s Dictionary of Slang

1. (US) an exciting, admirable or astonishing thing or person; often of a performance/performer.

[1768		A. Ross Helenore in Wattie Scot. Works (1938) 38: An’ for her dresses, wow, but they were fine!].
1918		‘German Throwed a Hand Grenade’ in J.J. Niles Singing Soldiers (1927) 58: Colonel says you’ll have to plough / Trenches, ’cause dis war’s a wow.
1923		H.C. Witwer Fighting Blood 152: I got a wow of a diamond scarf pin in it.
1925		G. Lee ‘Trouper Talk’ in AS I:1 37: The performers come leaping into the wings with the announcement that ‘She’s a wow!’.
1927		W. Edge Main Stem 176: She took three bends and an encore, and probably told her friends that number sure was a belly wow.
1930		R.E. Howard ‘Sailors’ Grudge’ Fight Stories Mar. 🌐 We are filming a peach, a pip and a wow! Is it a knockout? Oh, baby!
1935		M. Fulcher ‘Believe Me’ in Afro-American (Baltimore, MD) 23 May 12/4: Eulack Peacock, the Temple track wow.
1936		‘Banjo’ Paterson Shearer’s Colt 181: Ain’t that a wow of a notion?
1940		E. Curry Hysterical Hist. of Aus. 57: And were they wows, or were they wows?
1942		W. Winchell On Broadway 23 Sept. [synd. col.] It was a wow of a party.
1945		J. Henderson Gunner Inglorious (1974) 131: By crikey, you’re a wow, and no mistake.
1954		Oh Boy! No. 16 14: He’s a ‘reel wow!’.
1961		R.A. Norton Through Beatnik Eyeballs 77: You flip me, lady, like you a wow from Endsville.
1963		‘Geoffrey Tolhurst’ Flat 4 King’s Cross (1966) 13: I must have looked funny [...] a real small town girl on her way to the big city for the first time. I thought I was real wow, with my old cardboard suitcase, with my few clothes taking up only half of the space inside it.
1976		‘Hergé’ Tintin and the Picaros 51: It’s going to be a wow this year: thanks to us!
1983		(con. 1950s) D. Nobbs Second From Last in the Sack Race 216: You’ll be terrific after this. A wow. A two hundred per cent copper-bottomed wow.
1984		Benjamin & Pearl Limericks Down Under 48: [H]is sermons were wows [ibid.] 72: Said her only known lovers / ‘She’s a wow between th’ covers’.
2000		Indep. Rev. 14 Feb. 1: I can even do hot pants with pop socks, which is quite a wow, apparently.

2. in attrib. use of sense 1.

1940		C. Rawson Headless Lady (1987) 27: The Headless Lady is this season’s wow exhibit in the open-air amusement world.
1942		W. Winchell On Broadway 15 Mar. [synd. col.] After her last smash, ‘The Philly Story,’ and her wow flicker, ‘Woman of the Year’, Katie [Hepburn] is becoming [etc.].
2007		A.C. Shepard Woodward and Bernstein 263: ‘Carl came waltzing in. Bob was here, and people were paying rapt attention [...] It was a wow moment’.