bulletproof

adjective

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.

verb (used with object)

3. to make (something) bulletproof.

adjective

1. not penetrable by bulletsbulletproof glass

verb

2. (tr) to make bulletproof