buttercup vs butterflower

buttercup and butterflower both are nouns.

Word	Noun	Adjective	Verb	Adverb
buttercup	Yes	No	No	No
butterflower	Yes	No	No	No

As nouns, buttercup and butterflower are synonyms defined as:

buttercup and butterflower: any of various plants of the genus Ranunculus

Other synonyms of buttercup include butter-flower, crowfoot, goldcup, kingcup.

buttercup (noun)	butterflower (noun)
any of various plants of the genus Ranunculus	any of various plants of the genus Ranunculus