The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster]

   The fors and against. those in favor and those opposed; the
      pros and the cons; the advantages and the disadvantages.
      --Jane Austen.
      [1913 Webster]