man-to-man vs athletics

man-to-man is not a noun while athletics is a noun.

Word	Noun	Adjective	Verb	Adverb
man-to-man	No	Yes	No	Yes
athletics	Yes	No	No	No

man-to-man (noun)	athletics (noun)
	an active diversion requiring physical exertion and competition
	participation in sports events as an extracurricular activity
	a contest between athletes

man-to-man (adjective)	athletics (adjective)
forthright and honest
being a system of play in which an individual defensive player guards an individual offensive player

man-to-man (adverb)	athletics (adverb)
straightforwardly or frankly