Source : Webster's Revised Unabridged Dictionary (1913)

Dictatorial \Dic`ta*to"ri*al\, a. [Cf. F. dictatorial.]
   1. Pertaining or suited to a dictator; absolute.

            Military powers quite dictatorial.    --W. Irving.

   2. Characteristic of a dictator; imperious; dogmatical;
      overbearing; as, a dictatorial tone or manner. --
      {Dic`ta*to"ri*al*ly}, adv. -- {Dic`ta*to"ri*al*ness}, n.

Source : WordNet®

dictatorially
     adv : in an overbearingly domineering manner; as a dictator; "this
           manager acts dictatorially toward his colleagues" [syn:
            {autocratically}, {magisterially}]