unsounded vs unplumbed

unsounded and unplumbed both are adjectives.

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

As adjectives, unsounded and unplumbed are synonyms defined as:

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

Other synonyms of unsounded include profound, unfathomed.

unsounded (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
not made to sound