jockstrap UK /ˈd͡ʒɒkstɹæp/US /ˈd͡ʒɑkstɹæp/ noun1 •An athletic supporter worn by men and boys to support the genitals during strenuous exercise.With their jock-straps pinching, they slouch to attention While queueing for sarnies at the office canteen. — 1972 formsjockstraps