bulletproof

verbs

make bulletproof
"bulletproof the car"
bulletproof
is a type of (narrower)
make resistant (to harm)
"proof the materials against shrinking in the dryer"
proof

adjectives

without flaws or loopholes
"an ironclad contract"; "a watertight alibi"; "a bulletproof argument"
bulletproof, unassailable, unshakable, watertight
not penetrable by bullets
"bulletproof glass"; "bulletproof vest"
bulletproof
is similar to
protected by armor (used of persons or things military)
armored, armoured