The Collaborative International Dictionary of English v.0.48:

Unfrequented \Un`fre*quent"ed\, a. [Pref. un- + frequented.]
   Rarely visited; seldom or never resorted to by human beings;
   as, an unfrequented place or forest. --Addison.
   [1913 Webster]

WordNet (r) 3.0 (2006):

unfrequented
    adj 1: devoid of creatures; "a lonely crossroads"; "a solitary
           retreat"; "a trail leading to an unfrequented lake" [syn:
           lonely, solitary, unfrequented]

Moby Thesaurus II by Grady Ward, 1.0:

18 Moby Thesaurus words for "unfrequented":
   apart, detached, in a backwater, insular, isolated, out-of-the-way,
   out-of-the-world, quarantined, remote, removed, retired, secluded,
   segregated, separate, separated, shut off, unvisited, withdrawn