unusual vs unaccustomed

unusual and unaccustomed both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unusual	No	Yes	No	No
unaccustomed	No	Yes	No	No

unusual (adjective)	unaccustomed (adjective)
not usual or common or ordinary	unusual or unfamiliar
being definitely out of the ordinary and unexpected; slightly odd or even a bit weird
not commonly encountered