sea-poose vs undertide

sea-poose and undertide both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea-poose	Yes	No	No	No
undertide	Yes	No	No	No

As nouns, undertide is a hypernym of sea-poose; that is, undertide is a word with a broader meaning than sea-poose:

sea-poose: the seaward undercurrent created after waves have broken on the shore
undertide: a current below the surface of a fluid

Other hypernyms of sea-poose include undercurrent.

sea-poose (noun)	undertide (noun)
the seaward undercurrent created after waves have broken on the shore	a current below the surface of a fluid