swamp plant vs aquatic plant

swamp plant and aquatic plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
swamp plant	Yes	No	No	No
aquatic plant	Yes	No	No	No

As nouns, aquatic plant is a hypernym of swamp plant; that is, aquatic plant is a word with a broader meaning than swamp plant:

swamp plant: a semiaquatic plant that grows in soft wet land; most are monocots: sedge, sphagnum, grasses, cattails, etc; possibly heath
aquatic 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 swamp plant include hydrophyte, hydrophytic plant, water plant.

swamp plant (noun)	aquatic plant (noun)
a semiaquatic plant that grows in soft wet land; most are monocots: sedge, sphagnum, grasses, cattails, etc; possibly heath	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