Source : Webster's Revised Unabridged Dictionary (1913)

Overbearing \O`ver*bear"ing\, a.
   1. Overpowering; subduing; repressing. --I. Watts.

   2. Aggressively haughty; arrogant; domineering; tyrannical;
      dictatorial; insolent. --{O`ver*bear"ing*ly}, adv. --
      {O`ver*bear"ing*ness}, n.

Source : WordNet®

overbearingly
     adv : in an overbearing manner