unfathomed vs unplumbed

unfathomed and unplumbed both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unfathomed	No	Yes	No	No
unplumbed	No	Yes	No	No

As adjectives, unfathomed and unplumbed are synonyms defined as:

unfathomed and unplumbed: situated at or extending to great depth; too deep to have been sounded or plumbed

Other synonyms of unfathomed include profound, unsounded.

unfathomed (adjective)	unplumbed (adjective)
situated at or extending to great depth; too deep to have been sounded or plumbed	situated at or extending to great depth; too deep to have been sounded or plumbed