impregnable vs invulnerable

impregnable and invulnerable both are adjectives.

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

impregnable (adjective)	invulnerable (adjective)
capable of conceiving	immune to attack; impregnable
immune to attack; incapable of being tampered with
incapable of being overcome, challenged or refuted