magisterially

from WordNet (r) 3.0 (2006)

magisterially
    adv 1: in an overbearingly domineering manner; as a dictator;
           "this manager acts dictatorially toward his colleagues"
           [syn: {dictatorially}, {autocratically}, {magisterially}]
    2: in an authoritative and magisterial manner; "she spoke
       authoritatively" [syn: {authoritatively}, {magisterially}]

from The Collaborative International Dictionary of English v.0.48

Magisterially \Mag`is*te"ri*al*ly\, adv.
   In a magisterial manner.
   [1913 Webster]