/bool"it proohf'/ , 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.
[ 1855-60; BULLET + -PROOF ]