flatter vs suck up

flatter and suck up both are verbs.

Word	Noun	Adjective	Verb	Adverb
flatter	No	No	Yes	No
suck up	No	No	Yes	No

As verbs, suck up is a hyponym of flatter; that is, suck up is a word with a more specific, narrower meaning than flatter:

Other hyponyms of flatter include soft-soap, adulate, stroke, bootlick, fawn, kotow, kowtow, toady, truckle, brown-nose, butter up.

flatter (verb)	suck up (verb)
praise somewhat dishonestly	try to gain favor by cringing or flattering
	take in, also metaphorically
	ingratiate oneself to; often with insincere behavior