buckthorn vs ripple-grass

buckthorn and ripple-grass both are nouns.

Word	Noun	Adjective	Verb	Adverb
buckthorn	Yes	No	No	No
ripple-grass	Yes	No	No	No

As nouns, buckthorn and ripple-grass are synonyms defined as:

buckthorn and ripple-grass: an Old World plantain with long narrow ribbed leaves widely established in temperate regions

Other synonyms of buckthorn include English plantain, narrow-leaved plantain, Plantago lanceolata, ribgrass, ribwort.

buckthorn (noun)	ripple-grass (noun)
any shrub or small tree of the genus Bumelia	an Old World plantain with long narrow ribbed leaves widely established in temperate regions
a shrub or shrubby tree of the genus Rhamnus; fruits are source of yellow dyes or pigments
an Old World plantain with long narrow ribbed leaves widely established in temperate regions