sexual activity vs turn on

sexual activity is a noun but turn on is not a noun.

Word	Noun	Adjective	Verb	Adverb
sexual activity	Yes	No	No	No
turn on	No	No	Yes	No

sexual activity (noun)	turn on (noun)
activities associated with sexual intercourse

sexual activity (verb)	turn on (verb)
	become hostile towards
	get high, stoned, or drugged
	cause to operate by flipping a switch
	to evoke sexual feelings
	cause to be agitated, excited, or roused
	produce suddenly or automatically
	be contingent on