bulletproof vs unassailable

bulletproof and unassailable both are adjectives.

Word	Noun	Adjective	Verb	Adverb
bulletproof	No	Yes	Yes	No
unassailable	No	Yes	No	No

As adjectives, bulletproof and unassailable are synonyms defined as:

Other synonyms of bulletproof include ironclad, unshakable, watertight.

bulletproof (adjective)	unassailable (adjective)
not penetrable by bullets	without flaws or loopholes
without flaws or loopholes	impossible to assail
	immune to attack; incapable of being tampered with

bulletproof (verb)	unassailable (verb)
make bulletproof