hockey player vs participant

hockey player and participant both are nouns.

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

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

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

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