prize fight vs prizefight

prize fight and prizefight both are nouns.

Word	Noun	Adjective	Verb	Adverb
prize fight	Yes	No	No	No
prizefight	Yes	No	Yes	No

As nouns, prize fight and prizefight are synonyms defined as:

prize fight and prizefight: a boxing match between professional boxers for a cash prize

prize fight (noun)	prizefight (noun)
a boxing match between professional boxers for a cash prize	a boxing match between professional boxers for a cash prize

prize fight (verb)	prizefight (verb)
	box for a prize or money