untouchable vs inaccessible

untouchable is a noun but inaccessible is not a noun.

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

As adjectives, untouchable and inaccessible are synonyms defined as:

Other synonyms of untouchable include unobtainable, unprocurable.

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

untouchable (adjective)	inaccessible (adjective)
forbidden to the touch	capable of being reached only with great difficulty or not at all
impossible to assail	not capable of being obtained
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