sucking vs suck

sucking and suck both are nouns.

Word	Noun	Adjective	Verb	Adverb
sucking	Yes	No	No	No
suck	Yes	No	Yes	No

As nouns, sucking and suck are synonyms defined as:

Other synonyms of sucking include suction.

sucking (noun)	suck (noun)
the act of sucking	the act of sucking

sucking (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.