The Collaborative International Dictionary of English v.0.48:

Left-handed \Left"-hand`ed\, a.
   1. Having the left hand or arm stronger and more dexterous
      than the right; using the left hand and arm with more
      dexterity than the right.
      [1913 Webster]

   2. Clumsy; awkward; unlucky; insincere; sinister; malicious;
      as, a left-handed compliment.
      [1913 Webster]

            The commendations of this people are not always
            left-handed and detractive.           --Landor.
      [1913 Webster]

   3. Having a direction contrary to that of the hands of a
      watch when seen in front; -- said of a twist, a rotary
      motion, etc., looked at from a given direction.
      [1913 Webster]

   Left-handed marriage, a morganatic marriage. See
      Morganatic.

   Left-handed screw, a screw constructed to advance away from
      the observer, when turned, as in a nut, with a left-handed
      rotation. An ordinary wood screw is right-handed.
      [1913 Webster] Left-handedness

The Collaborative International Dictionary of English v.0.48:

Morganatic \Mor`ga*nat"ic\, a. [LL. matrimonium ad morganaticam,
   fr. morganatica a morning gift, a kind of dowry paid on the
   morning before or after the marriage, fr. OHG. morgan
   morning, in morgangeba morning gift, G. morgengabe. See
   Morn.]
   Pertaining to, in the manner of, or designating, a kind of
   marriage, called also left-handed marriage, between a man
   of superior rank and a woman of inferior, in which it is
   stipulated that neither the latter nor her children shall
   enjoy the rank or inherit the possessions of her husband.
   --Brande & C. -- Mor`ga*nat"ic*al*ly, adv.
   [1913 Webster]