feather-foil vs water plant

feather-foil and water plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
feather-foil	Yes	No	No	No
water plant	Yes	No	No	No

As nouns, water plant is a hypernym of feather-foil; that is, water plant is a word with a broader meaning than feather-foil:

feather-foil: a plant of the genus Hottonia
water plant: a plant that grows partly or wholly in water whether rooted in the mud, as a lotus, or floating without anchorage, as the water hyacinth

Other hypernyms of feather-foil include aquatic plant, hydrophyte, hydrophytic plant.

feather-foil (noun)	water plant (noun)
a plant of the genus Hottonia	a plant that grows partly or wholly in water whether rooted in the mud, as a lotus, or floating without anchorage, as the water hyacinth