Bulletproof - definition of bulletproof by The Free Dictionary
bul·let·proof (bo͝ol′ĭt-pro͞of′) adj. 1. Impenetrable by bullets. 2. Informal Impervious to assault, damage, or failure; guaranteed: a bulletproof method; bulletproof arguments. tr.v. bul·let·proofed, bul·let·proof·ing, bul·let·proofs To make impenetrable by bullets. American Heritage® Dictionary of …