undesirable vs unenviable

undesirable is a noun but unenviable is not a noun.

Word	Noun	Adjective	Verb	Adverb
undesirable	Yes	Yes	No	No
unenviable	No	Yes	No	No

undesirable (noun)	unenviable (noun)
one whose presence is undesirable

undesirable (adjective)	unenviable (adjective)
not wanted	hard to deal with; especially causing pain or embarrassment
not worthy of being chosen (especially as a spouse)	so undesirable as to be incapable of arousing envy