The Collaborative International Dictionary of English v.0.48:

Amenable \A*me"na*ble\, a. [F. amener to lead; ? (L. ad) = mener
   to lead, fr. L. minare to drive animals (properly by
   threatening cries), in LL. to lead; L. minari, to threaten,
   minae threats. See Menace.]
   1. (Old Law) Easy to be led; governable, as a woman by her
      husband. [Obs.] --Jacob.
      [1913 Webster]

   2. Liable to be brought to account or punishment; answerable;
      responsible; accountable; as, amenable to law.
      [1913 Webster]

            Nor is man too diminutive . . . to be amenable to
            the divine government.                --I. Taylor.
      [1913 Webster]

   3. Liable to punishment, a charge, a claim, etc.
      [1913 Webster]

   4. Willing to yield or submit; responsive; tractable.
      [1913 Webster]

            Sterling . . . always was amenable enough to
            counsel.                              --Carlyle.
      [1913 Webster]

WordNet (r) 3.0 (2006):

amenable
    adj 1: disposed or willing to comply; "someone amenable to
           persuasion" [syn: amenable, conformable]
    2: readily reacting to suggestions and influences; "a responsive
       student" [syn: amenable, tractable]
    3: open to being acted upon in a certain way; "an amenable
       hospitalization should not result in untimely death"; "the
       tumor was not amenable to surgical treatment"
    4: liable to answer to a higher authority; "the president is
       amenable to the constitutional court"

Moby Thesaurus II by Grady Ward, 1.0:

97 Moby Thesaurus words for "amenable":
   accessible, accommodating, accountable, acquiescent, adaptable,
   adapting, adaptive, adjusting, advance, agreeable, alacritous,
   ameliorate, amend, answerable, ardent, better, biddable,
   chargeable, compliant, consenting, content, cooperative, dependent,
   disposed, docile, eager, elevate, emend, enthusiastic, fain,
   favorable, favorably disposed, favorably inclined, forward, game,
   help, humble, impressionable, in the mind, in the mood, inclined,
   influenceable, liable, lift, malleable, meek, meliorate, mend,
   minded, movable, obedient, open, open-minded, passive, persuadable,
   persuasible, pervious, plastic, pliable, pliant, predisposed,
   promote, prompt, prone, quick, raise, ready, ready and willing,
   receptive, reconciled, rectify, repair, resigned, responsible,
   responsible for, responsive, right, suasible, subdued, subject,
   submissive, subordinate, suggestible, susceptible, swayable, tame,
   to blame, tractable, uncomplaining, unresisting, weak,
   well-disposed, well-inclined, willed, willing, willinghearted,
   zealous



Bouvier's Law Dictionary, Revised 6th Ed (1856):

AMENABLE. Responsible; subject to answer in a court of justice liable to
punishment.