impure vs untouchable

impure is not a noun while untouchable is a noun.

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

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

impure (adjective)	untouchable (adjective)
(used of persons or behaviors) immoral or obscene	forbidden to the touch
combined with extraneous elements	impossible to assail
having a physical or moral blemish so as to make impure according to dietary or ceremonial laws	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