Source : Webster's Revised Unabridged Dictionary (1913)

Favorable \Fa"vor*a*ble\, a. [Written also {favourable}.] [F.
   favorable, L. favorabilis favored, popular, pleasing, fr.
   favor. See {Favor}, n.]
   1. Full of favor; favoring; manifesting partiality; kind;
      propitious; friendly.

            Lend favorable ears to our request.   --Shak.

            Lord, thou hast been favorable unto thy land. --Ps.
                                                  lxxxv. 1.

   2. Conducive; contributing; tending to promote or facilitate;
      advantageous; convenient.

            A place very favorable for the making levies of men.
                                                  --Clarendon.

            The temper of the climate, favorable to generation,
            health, and long life.                --Sir W.
                                                  Temple.

   3. Beautiful; well-favored. [Obs.] --Spenser. --
      {Fa"vora*ble*ness}, n. -- {Fa"vor*a*bly}, sdv.

            The faborableness of the present times to all
            extertions in the cause of liberty.   --Burke.

Source : WordNet®

favourable
     adj 1: encouraging or approving or pleasing; "a favorable reply";
            "he received a favorable rating"; "listened with a
            favorable ear"; "made a favorable impression" [syn: {favorable}]
            [ant: {unfavorable}]
     2: (of winds or weather) tending to promote or facilitate; "the
        days were fair and the winds were favorable" [syn: {favorable}]
        [ant: {unfavorable}]
     3: at a convenient or suitable time; "an opportune time to
        receive guests" [syn: {favorable}, {opportune}]
     4: tending to favor or bring good luck; "miracles are
        auspicious accidents"; "encouraging omens"; "a favorable
        time to ask for a raise"; "lucky stars"; "a prosperous
        moment to make a decision" [syn: {auspicious}, {encouraging},
         {favorable}, {lucky}, {prosperous}]