water buttercup vs water crowfoot

water buttercup and water crowfoot both are nouns.

Word	Noun	Adjective	Verb	Adverb
water buttercup	Yes	No	No	No
water crowfoot	Yes	No	No	No

As nouns, water buttercup and water crowfoot are synonyms defined as:

water buttercup and water crowfoot: plant of ponds and slow streams having submerged and floating leaves and white flowers; Europe and North America

Other synonyms of water buttercup include Ranunculus aquatilis.

water buttercup (noun)	water crowfoot (noun)
plant of ponds and slow streams having submerged and floating leaves and white flowers; Europe and North America	plant of ponds and slow streams having submerged and floating leaves and white flowers; Europe and North America