/ Thesaurus / D Synonyms of deep sea Find synonyms for: Adjective1. deep-sea, marineusage: of or taking place in the deeper parts of the sea; "deep-sea fishing"; "deep-sea exploration"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: heifer Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language