role player vs player

role player and player both are nouns.

Word	Noun	Adjective	Verb	Adverb
role player	Yes	No	No	No
player	Yes	No	No	No

As nouns, role player and player are synonyms defined as:

Other synonyms of role player include actor, histrion, thespian.

role player (noun)	player (noun)
a theatrical performer	a theatrical performer
a person who makes deceitful pretenses	a person who participates in or is skilled at some game
	someone who plays a music as a profession
	a person who pursues a number of different social and sexual partners simultaneously
	someone who takes part in an activity