Source : Webster's Revised Unabridged Dictionary (1913)

Insecure \In`se*cure"\, a.
   1. Not secure; not confident of safety or permanence;
      distrustful; suspicious; apprehensive of danger or loss.

            With sorrow and insecure apprehensions. --Jer.
                                                  Taylor.

   2. Not effectually guarded, protected, or sustained; unsafe;
      unstable; exposed to danger or loss. --Bp. Hurg.

            The trade with Egypt was exceedingly insecure and
            precarious.                           --Mickle.

Source : WordNet®

insecure
     adj 1: not firm or firmly fixed; likely to fail or give way; "the
            hinge is insecure" [ant: {secure}]
     2: lacking in security or safety; "his fortune was increasingly
        insecure"; "an insecure future" [syn: {unsafe}] [ant: {secure}]
     3: lacking self-confidence or assurance; "an insecure person
        lacking mental stability" [ant: {secure}]
     4: not safe from attack [syn: {unsafe}]
     5: not financially safe or secure; "a bad investment"; "high
        risk investments"; "anything that promises to pay too much
        can't help being risky"; "speculative business
        enterprises" [syn: {bad}, {risky}, {high-risk}, {speculative}]