sea vs large indefinite amount

sea and large indefinite amount both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea	Yes	No	No	No
large indefinite amount	Yes	No	No	No

As nouns, large indefinite amount is a hypernym of sea; that is, large indefinite amount is a word with a broader meaning than sea:

sea: anything apparently limitless in quantity or volume
large indefinite amount: an indefinite quantity that is above the average in size or magnitude

Other hypernyms of sea include large indefinite quantity.

sea (noun)	large indefinite amount (noun)
a division of an ocean or a large body of salt water partially enclosed by land	an indefinite quantity that is above the average in size or magnitude
turbulent water with swells of considerable size
anything apparently limitless in quantity or volume