butter-flower vs buttercup

butter-flower and buttercup both are nouns.

Word	Noun	Adjective	Verb	Adverb
butter-flower	Yes	No	No	No
buttercup	Yes	No	No	No

As nouns, butter-flower and buttercup are synonyms defined as:

butter-flower and buttercup: any of various plants of the genus Ranunculus

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

butter-flower (noun)	buttercup (noun)
any of various plants of the genus Ranunculus	any of various plants of the genus Ranunculus