sexual activity vs suck

sexual activity and suck both are nouns.

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

sexual activity (noun)	suck (noun)
activities associated with sexual intercourse	the act of sucking

sexual activity (verb)	suck (verb)
	give suck to
	draw into the mouth by creating a practical vacuum in the mouth
	take in, also metaphorically
	draw something in by or as if by a vacuum
	provide sexual gratification through oral stimulation
	be inadequate or objectionable
	attract by using an inexorable force, inducement, etc.