The Collaborative International Dictionary of English v.0.48:

Distinguishing \Dis*tin"guish*ing\, a.
   Constituting difference, or distinction from everything else;
   distinctive; peculiar; characteristic.
   [1913 Webster]

         The distinguishing doctrines of our holy religion.
                                                  --Locke.
   [1913 Webster]

   Distinguishing pennant (Naut.), a special pennant by which
      any particular vessel in a fleet is recognized and
      signaled. --Simmonds.
      [1913 Webster]