Green’s Dictionary of Slang

suffering from venereal disease.

1937		‘Boxcar Bertha’ Sister of the Road (1975) 163: This little bitch belongs to me [...] She was a no-account clappy litle chippy when I found her.
1964		B. Jackson Get Your Ass in the Water (1974) 107: You ass ain’t no good, all beat and clappy, / get your kicks from suckin’ dicks and fuckin’ your bald-headed pappy.
1969		‘Iceberg Slim’ Pimp 112: His voice was a squeal like a clappy joker makes when the croaker rams a ‘sound’ down his ‘dingus’.
1969		T. Kochman ‘“Rapping” in the Black Ghetto’Trans-action Feb. 33/2: ‘[O]l meat-beating Reese rather screw that cross-eyed, clapsy bitch’.