c. 1600, of unknown origin, perhaps from Middle French pimpant "alluring in dress, seductive," present participle of pimper "to dress elegantly" (16c.), from Old French pimpelorer, pipelorer "decorate, color, beautify." Weekley suggests Middle French pimpreneau, defined in Cotgrave [French-English Dictionary, 1611] as "a knave, rascall, varlet, scoundrell," but Liberman is against this.
Judging by such recorded meanings of pimp as 'helper in mines; servant in logging camps,' this word was originally applied to boys and servants. [Liberman]
The word also means "informer, stool pigeon" in Australia and New Zealand and in South Africa, where by early 1960s it existed in Swahili form impimpsi. Pimpmobile first recorded 1973 (six years before Popemobile).
PIMP. A male procurer, or cock bawd; also a small faggot used about London for lighting fires, named from introducing the fire to the coals. [Grose, "Dictionary of the Vulgar Tongue," London, 1785]