The Collaborative International Dictionary of English v.0.48:

Uninformed \Uninformed\
   See informed.

WordNet (r) 3.0 (2006):

uninformed
    adj 1: not informed; lacking in knowledge or information; "the
           uninformed public" [ant: informed]

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "uninformed":
   awkward, blankminded, callow, dumb, empty, empty-headed, gauche,
   green, groping, ignorant, inane, incognizant, inexpectant,
   inexperienced, innocent, know-nothing, naive, nescient,
   nonexpectant, oblivious, raw, simple, strange to, tentative,
   unacquainted, unadmonished, unadvised, unanticipating,
   unanticipative, unapprized, unaware, uncomprehending, unconversant,
   unenlightened, unexpecting, unfamiliar, unforewarned, unguessing,
   unilluminated, uninitiated, uninstructed, unintelligent, unknowing,
   unposted, unprepared, unready, unripe, unsure, unsuspecting,
   unversed, unwarned, unwitting, vacuous