participant vs groom

participant and groom both are nouns.

Word	Noun	Adjective	Verb	Adverb
participant	Yes	No	No	No
groom	Yes	No	Yes	No

As nouns, groom is a hyponym of participant; that is, groom is a word with a more specific, narrower meaning than participant:

participant (noun)	groom (noun)
someone who takes part in an activity	a man who has recently been married
a person who participates in or is skilled at some game	someone employed in a stable to take care of the horses
	a man participant in his own marriage ceremony

participant (verb)	groom (verb)
	care for one's external appearance
	give a neat appearance to
	educate for a future role or function