unplumbed vs unsounded

unplumbed and unsounded both are adjectives.

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

As adjectives, unplumbed and unsounded are synonyms defined as:

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

Other synonyms of unplumbed include profound, unfathomed.

unplumbed (adjective)	unsounded (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