sexual activity vs energise

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

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

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

sexual activity (verb)	energise (verb)
	cause to be alert and energetic
	raise to a higher energy level