bulletproof

UK: /ˈbʊlɪtpruːf/ US: /ˈbʊlɪtˌpruf/ ,(bŏŏl′it pro̅o̅f′)

WordReference Random House Learner's Dictionary of American English © 2026

bul•let•proof /ˈbʊlɪtˌpruf/   adj. 

1. (of vehicles, clothing, etc.) capable of absorbing or reducing the impact of a bullet:
   a bulletproof vest.

WordReference Random House Unabridged Dictionary of American English © 2026

bul•let•proof  (bŏŏl′it pro̅o̅f′), adj. 

1. (of vehicles, glass, clothing, etc.) capable of resisting or absorbing the impact of a bullet.
2. [Informal.] safe from failure;
   without errors or shortcomings and beyond criticism:
   a bulletproof system; a bulletproof budget.

v.t. 

3. to make (something) bulletproof.

• bullet + -proof 1855–60

Collins Concise English Dictionary © HarperCollins Publishers::

bulletproof / ˈbʊlɪtˌpruːf/ adjective

1. not penetrable by bullets

verb

1. (transitive) to make bulletproof