sexual activity vs extracurricular

sexual activity is a noun but extracurricular is not a noun.

Word	Noun	Adjective	Verb	Adverb
sexual activity	Yes	No	No	No
extracurricular	No	Yes	No	No

sexual activity (noun)	extracurricular (noun)
activities associated with sexual intercourse

sexual activity (adjective)	extracurricular (adjective)
	characterized by adultery
	outside the regular duties of your job or profession
	outside the regular academic curriculum