slapper UK /ˈslæpə/US /ˈslæpɚ/noun 5forms 1phrases 1 noun5 •One who, or that which, slaps. •(slang, offensive) A prostitute.A fella looking dapper / And he's sittin' with a slapper / Then I see it's a pimp / And his crack whore — 2006 •(UK, slang) A woman of loose morals. •A type of detonator which uses a powerful surge of electricity to vaporize a thin metal foil, propelling a larger piece of plastic film at a speed high enough to detonate an explosive upon impact. •(slang, no longer used) Anything monstrous; a whopper. formsslappers Phrases with slapper knee-slapperA joke, especially one which strikes the listener or reader as particularly humorous.