foot race vs funrun

foot race and funrun both are nouns.

Word	Noun	Adjective	Verb	Adverb
foot race	Yes	No	No	No
funrun	Yes	No	No	No

As nouns, funrun is a hyponym of foot race; that is, funrun is a word with a more specific, narrower meaning than foot race:

foot race: a race run on foot
funrun: a footrace run for fun (often including runners who are sponsored for a charity)

Other hyponyms of foot race include fun run, marathon, obstacle race, steeplechase, track event.

foot race (noun)	funrun (noun)
a race run on foot	a footrace run for fun (often including runners who are sponsored for a charity)