unobtainable vs untouchable

unobtainable is not a noun while untouchable is a noun.

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

As adjectives, unobtainable and untouchable are synonyms defined as:

Other synonyms of unobtainable include inaccessible, unprocurable.

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

unobtainable (adjective)	untouchable (adjective)
not capable of being obtained	forbidden to the touch
	impossible to assail
	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