player vs leading man

player and leading man both are nouns.

Word	Noun	Adjective	Verb	Adverb
player	Yes	No	No	No
leading man	Yes	No	No	No

As nouns, leading man is a hyponym of player; that is, leading man is a word with a more specific, narrower meaning than player:

player (noun)	leading man (noun)
a theatrical performer	actor who plays the leading male role
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