1. 
[syn: uncertain, unsure, incertain]
The Collaborative International Dictionary of English v.0.48:
Incertain \In*cer"tain\, n. [Pref. in- not + certain: cf. F.
   incertain, L. incertus. See Certain.]
   Uncertain; doubtful; unsteady. -- In*cer"tain*ly, adv.
   [1913 Webster]
         Very questionable and of uncertain truth. --Sir T.
                                                  Browne.
   [1913 Webster]
WordNet (r) 3.0 (2006):
incertain
    adj 1: 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]