casteless vs outcaste

casteless is not a noun while outcaste is a noun.

Word	Noun	Adjective	Verb	Adverb
casteless	No	Yes	No	No
outcaste	Yes	Yes	No	No

As adjectives, casteless and outcaste are synonyms defined as:

casteless and outcaste: not belonging to or having been expelled from a caste and thus having no place or status in society

casteless (noun)	outcaste (noun)
	a person belonging to no caste

casteless (adjective)	outcaste (adjective)
not belonging to or having been expelled from a caste and thus having no place or status in society	not belonging to or having been expelled from a caste and thus having no place or status in society