unplumbed vs unfathomed

unplumbed and unfathomed both are adjectives.

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

As adjectives, unplumbed and unfathomed are synonyms defined as:

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

Other synonyms of unplumbed include profound, unsounded.

unplumbed (adjective)	unfathomed (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