invulnerable vs bombproof

invulnerable is not a noun while bombproof is a noun.

Word	Noun	Adjective	Verb	Adverb
invulnerable	No	Yes	No	No
bombproof	Yes	Yes	Yes	No

invulnerable (noun)	bombproof (noun)
	a chamber (often underground) reinforced against bombing and provided with food and living facilities; used during air raids

invulnerable (adjective)	bombproof (adjective)
immune to attack; impregnable	able to resist the explosive force of bombs and shells

invulnerable (verb)	bombproof (verb)
	make safe against bombings