bulletproof

(verb) make bulletproof. Example: "Bulletproof the car."

(adj) without flaws or loopholes. Synonyms: unassailable, unshakable, watertight. Examples: "An ironclad contract." "A watertight alibi." "A bulletproof argument."

(adj) not penetrable by bullets. Examples: "Bulletproof glass." "Bulletproof vest."