The Collaborative International Dictionary of English v.0.48:

Unexplored \Unexplored\
   See explored.

WordNet (r) 3.0 (2006):

unexplored
    adj 1: not yet discovered; "undiscovered islands" [syn:
           undiscovered, unexplored]

Moby Thesaurus II by Grady Ward, 1.0:

48 Moby Thesaurus words for "unexplored":
   able, enigmatic, incalculable, incognizable, invisible, mysterious,
   puzzling, sealed, strange, unapparent, unapprehended,
   unascertained, unbeknown, uncharted, unclassified, unconsidered,
   undetected, undisclosed, undiscoverable, undiscovered, undivulged,
   unexamined, unexplained, unexposed, unfamiliar, unfathomed,
   unheard, unheard-of, unidentified, uninvestigated, unknowable,
   unknown, unperceived, unplumbed, unrevealed, unscanned, unsearched,
   unseen, unsifted, unsolved, unspied, unstudied, unsuspected,
   untouched, untraced, untracked, unweighed, virgin