Source : Webster's Revised Unabridged Dictionary (1913)

Backhanded \Back"hand`ed\, a.
   1. With the hand turned backward; as, a backhanded blow.

   2. Indirect; awkward; insincere; sarcastic; as, a backhanded
      compliment.

   3. Turned back, or inclining to the left; as, a backhanded
      letters.

Source : WordNet®

backhanded
     adj 1: (of racket strokes) made across the body with back of hand
            facing direction of stroke [syn: {backhand(a)}] [ant:
            {forehand(a)}]
     2: roundabout or ambiguous; "attacks from tht source amounted
        to a backhanded compliment to his integrity"; "a
        backhanded and dishonest way of reaching his goal"