The Collaborative International Dictionary of English v.0.48:

Affable \Af"fa*ble\, a. [F. affable, L. affabilis, fr. affari to
   speak to; ad + fari to speak. See Fable.]
   1. Easy to be spoken to or addressed; receiving others kindly
      and conversing with them in a free and friendly manner;
      courteous; sociable.
      [1913 Webster]

            An affable and courteous gentleman.   --Shak.
      [1913 Webster]

            His manners polite and affable.       --Macaulay.
      [1913 Webster]

   2. Gracious; mild; benign.
      [1913 Webster]

            A serene and affable countenance.     --Tatler.
      [1913 Webster]

   Syn: Courteous; civil; complaisant; accessible; mild; benign;
        condescending.
        [1913 Webster]

WordNet (r) 3.0 (2006):

affable
    adj 1: diffusing warmth and friendliness; "an affable smile";
           "an amiable gathering"; "cordial relations"; "a cordial
           greeting"; "a genial host" [syn: affable, amiable,
           cordial, genial]

Moby Thesaurus II by Grady Ward, 1.0:

119 Moby Thesaurus words for "affable":
   Bohemian, accommodating, agreeable, amiable, amicable, attentive,
   benevolent, benign, benignant, blissful, bonhomous, casual,
   cheerful, civil, clubbable, clubbish, clubby, communicative,
   companionable, companionate, compatible, complaisant, compliant,
   congenial, considerate, cordial, courteous, decent, deferential,
   degage, desirable, dulcet, easy, easy-natured, easygoing,
   en rapport, enjoyable, fair, fair and pleasant, familiar,
   felicific, felicitous, fine, fit for society, folksy,
   fond of society, free and easy, friendly, generous, genial, gentle,
   good, good-humored, good-natured, good-tempered, goodly, graceful,
   gracious, grateful, gratifying, gregarious, harmonious, haymish,
   heart-warming, homely, homey, honeyed, hospitable, indulgent,
   informal, irregular, kind, kindly, likable, loose, loquacious,
   mellifluous, mellow, mild, natural, nice, obliging, offhand,
   offhanded, overindulgent, overpermissive, permissive, plain,
   pleasant, pleasing, pleasurable, pleasure-giving, pleasureful,
   polite, relaxed, respectful, rewarding, satisfying, simple,
   sociable, social, social-minded, solicitous, suave, sweet,
   sweet-tempered, tactful, talkative, thoughtful, unaffected,
   unassuming, unceremonious, unconstrained, unconventional,
   unofficial, unstudied, urbane, welcome, well-natured