Green’s Dictionary of Slang

1. (orig. US) used to express sudden or speedy movement; esp. of a boxer’s punches.

1910		Charlotte News (NC) 27 Mar. 18/1: [Bat nelson] always let them work themselves out on his ribs [...] But when they were tired — wham! bam! Curtains.
1926		Arizona Republican (Phoenix, AZ) 26 Aug. 6/6: [advert] Wham-Bam! and another guy bit canvas.
1932		Logansport Pharos-Trib. (IN) 27 Sept. 5/8: Carefully and cooly Max measured his man. Wham. Bam. Again Walker hit the canvas.
1947		Altoona Trib. (PA) 25 Dec. 13/7: Van Buren, the wham bam kid from Louisiana.
1956		Billie Holiday Lady Sings the Blues (1975) 25: With my regular white customers, it was a cinch. They had wives and kids to go home to. When they came to see me it was wham, bang, they gave me the money and were gone. [Ibid.] 27: ‘I thought I was giving you a chance,’ she spouted at me. ‘But you turned out to be a girl of bad character.’ Wham, bang, four months she handed me.
1976		R. Price Blood Brothers 185: Fuck you, fuck me, fuck us, wham bam out the door, bye-bye, Stony.
1987		(con. c.1967) J. Ferrandino Firefight 148: Next thing, whambam, they sent us to this motherfucker.

2. used as adv. emphatically.

2023

(con. 1962) J. Ellroy Enchanters 32: I leaned close [...] I ticked points, wham-bam.