Source : Webster's Revised Unabridged Dictionary (1913)

Unwary \Un*wa"ry\, a. [Cf. {Unware}.]
   1. Not vigilant against danger; not wary or cautious;
      unguarded; precipitate; heedless; careless.

   2. Unexpected; unforeseen; unware. [Obs.] --Spenser.

Source : WordNet®

unwary
     adj : not alert to danger or deception; "the shrieks of unwary
           animals taken by surprise"; "some thieves prey
           especially on unwary travelers"; "seduce the unwary
           reader into easy acquiescence"- O.J.Campbell [ant: {wary}]