bulletproof
1. [ adjective ] without flaws or loopholes
Synonyms: unassailable unshakable watertight ironclad
Examples:

"an ironclad contract" "a watertight alibi" "a bulletproof argument"

Related terms: incontestable
2. [ adjective ] not penetrable by bullets
Examples:

"bulletproof glass" "bulletproof vest"

Related terms: armored
Similar spelling:   bullet_vote
  built-up