Source : Webster's Revised Unabridged Dictionary (1913)

For \For\, n.
   One who takes, or that which is said on, the affrimative
   side; that which is said in favor of some one or something;
   -- the antithesis of against, and commonly used in connection
   with it.

   {The fors and against}. those in favor and those opposed; the
      pros and the cons; the advantages and the disadvantages.
      --Jane Austen.