expressionless vs unexpressive

expressionless and unexpressive both are adjectives.

Word	Noun	Adjective	Verb	Adverb
expressionless	No	Yes	No	No
unexpressive	No	Yes	No	No

As adjectives, expressionless and unexpressive are synonyms defined as:

Other synonyms of expressionless include deadpan, impassive, poker-faced.

expressionless (adjective)	unexpressive (adjective)
deliberately impassive in manner	deliberately impassive in manner