unassailable vs untouchable

unassailable is not a noun while untouchable is a noun.

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

As adjectives, unassailable and untouchable are synonyms defined as:

unassailable (noun)	untouchable (noun)
	belongs to lowest social and ritual class in India

unassailable (adjective)	untouchable (adjective)
without flaws or loopholes	forbidden to the touch
impossible to assail	impossible to assail
immune to attack; incapable of being tampered with	beyond the reach of criticism or attack or impeachment
	not capable of being obtained
	(especially used in traditional Hindu belief of the lowest caste or castes) defiling