suck vs suckle

suck is a noun but suckle is not a noun.

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

As verbs, suck and suckle are synonyms defined as:

Other synonyms of suck include breastfeed, give suck, lactate, nurse, wet-nurse.

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

suck (verb)	suckle (verb)
give suck to	give suck to
draw into the mouth by creating a practical vacuum in the mouth	suck milk from the mother's breasts
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.