sexual activity vs immoral

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

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

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

sexual activity (adjective)	immoral (adjective)
	deliberately violating accepted principles of right and wrong
	not adhering to ethical or moral principles