I. ˈ ̷ ̷ ̷ ̷| ̷ ̷ adjective
1. : impenetrable to bullets
bulletproof glass
2. : not subject to correction, alteration, or modification
a bulletproof argument
II. transitive verb
( -ed/-ing/-s )
Etymology: bulletproof (I)
: to make impenetrable to bullets
bulletproof a car