athletics vs sit out

athletics is a noun but sit out is not a noun.

Word	Noun	Adjective	Verb	Adverb
athletics	Yes	No	No	No
sit out	No	No	Yes	No

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

athletics (verb)	sit out (verb)
	endure to the end
	not participate in (an activity, such as a dance or a sports event)