authoritatively

from WordNet (r) 3.0 (2006)
authoritatively
    adv 1: in an authoritative and magisterial manner; "she spoke
           authoritatively" [syn: {authoritatively},
           {magisterially}]
    
from The Collaborative International Dictionary of English v.0.48
Authoritative \Au*thor"i*ta*tive\, a.
   1. Having, or proceeding from, due authority; entitled to
      obedience, credit, or acceptance; determinate; commanding.
      [1913 Webster]

            The sacred functions of authoritative teaching.
                                                  --Barrow.
      [1913 Webster]

   2. Having an air of authority; positive; dictatorial;
      peremptory; as, an authoritative tone.
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            The mock authoritative manner of the one, and the
            insipid mirth of the other.           --Swift.
      [1913 Webster] -- {Au*thor"i*ta*tive*ly}, adv. --
      {Au*thor"i*ta*tive*ness}, n.
      [1913 Webster]
    

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