mid-15c., bottyne "plunder taken from an enemy in war," from Old French butin "booty" (14c.), from a Germanic source akin to Middle Low German bute "exchange." Influenced in form and sense (toward "profit, gain," whether taken by force or not) by boot (n.2) and in form by nouns ending in -y. Meaning "female body considered as a sex object" is 1920s, African-American vernacular. As with other male sexual terms for women, its sense can shift to copulation generally or to the eroticized body parts (compare nookie, ass, etc.).
