unplumbed
1. [ adjective ] situated at or extending to great depth; too deep to have been sounded or plumbed
Synonyms: unfathomed unsounded profound
Examples:

"the profound depths of the sea" "the dark unfathomed caves of ocean"-Thomas Gray "unplumbed depths of the sea" "remote and unsounded caverns"

Related terms: deep
Similar spelling:   unvalued
  unploughed
  unblemished
  unplowed
  unplaced
  unflawed
  unplug
  unpledged
  unpleated
  unplanted
  unplanned
  unfledged
  unblessed
  unblended