Source : Webster's Revised Unabridged Dictionary (1913)

Fraternize \Fra"ter*nize\ (? or ?; 277), v. i. [imp. & p. p.
   {Fraternized}; p. pr. & vb. n.. {Fraternizing}.] [Cf. F.
   fraterniser.]
   To associate or hold fellowship as brothers, or as men of
   like occupation or character; to have brotherly feelings.

Fraternize \Fra"ter*nize\, v. t.
   To bring into fellowship or brotherly sympathy.

         Correspondence for fraternizing the two nations.
                                                  --Burke.

Source : WordNet®

fraternize
     v : be on friendly terms with someone, as if with a brother,
         especially with an enemy [syn: {fraternise}]