underarm vs athletics

underarm is not a noun while athletics is a noun.

Word	Noun	Adjective	Verb	Adverb
underarm	No	Yes	No	Yes
athletics	Yes	No	No	No

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

underarm (adjective)	athletics (adjective)
with hand brought forward and up from below shoulder level

underarm (adverb)	athletics (adverb)
with the hand swung below shoulder level