unfathomed

from WordNet (r) 3.0 (2006)

unfathomed
    adj 1: situated at or extending to great depth; too deep to have
           been sounded or plumbed; "the profound depths of the
           sea"; "the dark unfathomed caves of ocean"-Thomas Gray;
           "unplumbed depths of the sea"; "remote and unsounded
           caverns" [syn: {profound}, {unfathomed}, {unplumbed},
           {unsounded}]

from The Collaborative International Dictionary of English v.0.48

Unfathomed \Unfathomed\
   See {fathomed}.

from Moby Thesaurus II by Grady Ward, 1.0

57 Moby Thesaurus words for "unfathomed":
      able, abysmal, abyssal, bottomless, cavernous, colossal,
      deep as hell, enigmatic, enormous, fathomless, gaping, immense,
      incalculable, incognizable, massive, mighty, monstrous, mysterious,
      plumbless, plunging, prodigious, puzzling, sealed, soundless,
      strange, tremendous, unapparent, unapprehended, unascertained,
      unbeknown, uncharted, unclassified, undisclosed, undiscoverable,
      undiscovered, undivulged, unexplained, unexplored, unexposed,
      unfamiliar, unfathomable, unheard, unheard-of, unidentified,
      uninvestigated, unknowable, unknown, unperceived, unplumbed,
      unrevealed, unsounded, unsuspected, untouched, vast, virgin,
      without bottom, yawning