football player vs participant

football player and participant both are nouns.

Word	Noun	Adjective	Verb	Adverb
football player	Yes	No	No	No
participant	Yes	No	No	No

As nouns, participant is a hypernym of football player; that is, participant is a word with a broader meaning than football player:

Other hypernyms of football player include athlete, jock, player.

football player (noun)	participant (noun)
an athlete who plays American football	someone who takes part in an activity
	a person who participates in or is skilled at some game