Source : Webster's Revised Unabridged Dictionary (1913)

Scrub \Scrub\, a.
   Mean; dirty; contemptible; scrubby.

         How solitary, how scrub, does this town look!
                                                  --Walpole.

         No little scrub joint shall come on my board. --Swift.

   {Scrub game}, a game, as of ball, by unpracticed players.

   {Scrub race}, a race between scrubs, or between untrained
      animals or contestants.