Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
unplumbed is an adjective meaning "situated at or extending to great depth; too deep to have been sounded or plumbed". It carries one recorded sense.
situated at or extending to great depth; too deep to have been sounded or plumbed
“the profound depths of the sea”
“the dark unfathomed caves of ocean”
“unplumbed depths of the sea”
“remote and unsounded caverns”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for unplumbed come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.