bulletproof

Short definition from Wiktionary

Adjective

1. 1
   Capable of withstanding a direct shot by a bullet fired from a gun.
2. 2
   Reliable, infallible, sturdy or error-tolerant.

Verb

1. 1
   To make proof against bullets.
2. 2
   To make resistant to failure.

Noun

1. 1
   A liquor store