sex activity vs energise

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

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

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

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