Source : Webster's Revised Unabridged Dictionary (1913)

Magisterial \Mag`is*te"ri*al\, a. [L. magisterius magisterial.
   See {Master}.]
   1. Of or pertaining to a master or magistrate, or one in
      authority; having the manner of a magister; official;
      commanding; authoritative. Hence: Overbearing;
      dictatorial; dogmatic.

            When magisterial duties from his home Her father
            called.                               --Glover.

            We are not magisterial in opinions, nor,
            dictator-like, obtrude our notions on any man. --Sir
                                                  T. Browne.

            Pretenses go a great way with men that take fair
            words and magisterial looks for current payment.
                                                  --L'Estrange.

   2. (Alchem. & Old Chem.) Pertaining to, produced by, or of
      the nature of, magistery. See {Magistery}, 2.

   Syn: Authoritative; stately; august; pompous; dignified;
        lofty; commanding; imperious; lordly; proud; haughty;
        domineering; despotic; dogmatical; arrogant.

   Usage: {Magisterial}, {Dogmatical}, {Arrogant}. One who is
          magisterial assumes the air of a master toward his
          pupils; one who is dogmatical lays down his positions
          in a tone of authority or dictation; one who is
          arrogant in sults others by an undue assumption of
          superiority. Those who have long been teachers
          sometimes acquire, unconsciously, a manner which
          borders too much on the magisterial, and may be
          unjustly construed as dogmatical, or even arrogant.

Source : WordNet®

magisterial
     adj 1: of or relating to a magistrate; "official magisterial
            functions"
     2: offensively self-assured or given to exercising usually
        unwarranted power; "an autocratic person"; "autocratic
        behavior"; "a bossy way of ordering others around"; "a
        rather aggressive and dominating character"; "managed the
        employees in an aloof magisterial way"; "a swaggering
        peremptory manner" [syn: {autocratic}, {bossy}, {dominating},
         {high-and-mighty}, {peremptory}]
     3: used of a person's appearance or behavior; befitting an
        eminent person; "his distinguished bearing"; "the
        monarch's imposing presence"; "she reigned in magisterial
        beauty" [syn: {distinguished}, {imposing}]