[syn: uncertain, unsure, incertain]
The Collaborative International Dictionary of English v.0.48:
Unsure \Unsure\
   See sure.
WordNet (r) 3.0 (2006):
unsure
    adj 1: lacking self-confidence; "stood in the doorway diffident
           and abashed"; "problems that call for bold not timid
           responses"; "a very unsure young man" [syn: diffident,
           shy, timid, unsure] [ant: confident]
    2: lacking or indicating lack of confidence or assurance;
       "uncertain of his convictions"; "unsure of himself and his
       future"; "moving with uncertain (or unsure) steps"; "an
       uncertain smile"; "touched the ornaments with uncertain
       fingers" [syn: uncertain, unsure, incertain] [ant:
       certain(p), sure]
Moby Thesaurus II by Grady Ward, 1.0:
122 Moby Thesaurus words for "unsure":
   agnostic, ambiguous, awkward, blankminded, borderline, callow,
   capricious, chancy, changeable, dangerous, desultory, dicey,
   dickey, doubtful, doubting, dubious, dumb, empty, empty-headed,
   equivocal, erratic, fickle, fluctuant, fly-by-night, gauche, green,
   groping, hazardous, hesitant, hesitating, ignorant, inane,
   incalculable, indecisive, indemonstrable, inexperienced, infirm,
   innocent, insecure, insubstantial, irresolute, irresponsible,
   know-nothing, naive, nescient, open, perilous, polysemous,
   precarious, problematic, provisional, questionable, raw, risky,
   rocky, rootless, shaky, shifting, shifty, simple, skeptical,
   slippery, strange to, suspicious, temporary, tentative, ticklish,
   tottery, touch-and-go, treacherous, trustless, unaccountable,
   unacquainted, unapprized, unassured, uncertain, unclear,
   uncomprehending, unconfident, unconfirmable, unconversant,
   unconvinced, undecided, undependable, undivinable, unenlightened,
   unfaithworthy, unfamiliar, unforeseeable, unhealthy, unilluminated,
   uninformed, uninitiated, unintelligent, unknowing, unpersuaded,
   unposted, unpredictable, unprovable, unreliable, unripe, unsafe,
   unselfassured, unselfconfident, unselfreliant, unsolid, unsound,
   unstable, unsteadfast, unsteady, unsubstantial, untrustworthy,
   untrusty, unverifiable, unversed, vacillating, vacuous, variable,
   wavering, weak, whimsical, wobbly