The Collaborative International Dictionary of English v.0.48:

Favorable \Fa"vor*a*ble\ (f[=a]"v[~e]r*[.a]*b'l), 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.
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            Lend favorable ears to our request.   --Shak.
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            Lord, thou hast been favorable unto thy land. --Ps.
                                                  lxxxv. 1.
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   2. Conducive; contributing; tending to promote or facilitate;
      advantageous; convenient.
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            A place very favorable for the making levies of men.
                                                  --Clarendon.
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            The temper of the climate, favorable to generation,
            health, and long life.                --Sir W.
                                                  Temple.
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   3. Beautiful; well-favored. [Obs.] --Spenser. --
      Fa"vora*ble*ness, n. -- Fa"vor*a*bly, adv.
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            The favorableness of the present times to all
            exertions in the cause of liberty.    --Burke.
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WordNet (r) 3.0 (2006):

favorably
    adv 1: showing approval; "he reviewed the play favorably" [syn:
           favorably, favourably] [ant: unfavorably,
           unfavourably]