The Collaborative International Dictionary of English v.0.48:

Accomplishment \Ac*com"plish*ment\ (-ment), n. [F.
   accomplissement, fr. accomplir.]
   1. The act of accomplishing; entire performance; completion;
      fulfillment; as, the accomplishment of an enterprise, of a
      prophecy, etc.
      [1913 Webster]

   2. That which completes, perfects, or equips thoroughly;
      acquirement; attainment; that which constitutes excellence
      of mind, or elegance of manners, acquired by education or
      training. "My new accomplishment of dancing." --Churchill.
      "Accomplishments befitting a station." --Thackeray.
      [1913 Webster]

            Accomplishments have taken virtue's place,
            And wisdom falls before exterior grace. --Cowper.
      [1913 Webster]

WordNet (r) 3.0 (2006):

accomplishment
    n 1: the action of accomplishing something [syn:
         accomplishment, achievement]
    2: an ability that has been acquired by training [syn: skill,
       accomplishment, acquirement, acquisition, attainment]

Moby Thesaurus II by Grady Ward, 1.0:

157 Moby Thesaurus words for "accomplishment":
   ability, accomplished fact, accomplishments, achievement,
   acquirement, acquisition of knowledge, acquisitions, act, acta,
   action, administration, advance, advancement, advent, adventure,
   amplification, answer, appearance, approach, arrival,
   ascertainment, attainment, attainments, blossoming, blow,
   bringing to fruition, clearing up, coming, commission, completion,
   conclusion, conduct, consummation, coup, cracking, culmination,
   dealings, decipherment, decoding, deed, denouement, determination,
   development, developmental change, discharge, disentanglement,
   dispatch, doing, doings, edification, education, effectuation,
   effort, elaboration, enactment, end, end result, endeavor,
   enlargement, enlightenment, enterprise, evolution,
   evolutionary change, evolvement, evolving, execution, expansion,
   explanation, explication, exploit, fait accompli, feat, finding,
   finding-out, finish, flowering, fortunate outcome, furtherance,
   gest, gift, go, gradual change, growth, hand, handiwork, handling,
   illumination, implementation, instruction, interpretation, issue,
   job, learning, liberal education, management, maneuver, maturation,
   measure, move, natural development, natural growth,
   nonviolent change, operation, outcome, overproduction, overt act,
   passage, performance, perpetration, proceeding, production,
   productiveness, progress, progression, prosperity,
   prosperous issue, reaching, realization, reason, res gestae,
   resolution, resolving, result, riddling, ripening, rise, skill,
   solution, solving, sophistication, sorting out, step,
   store of knowledge, stroke, stunt, success, talent, thing,
   thing done, tour de force, transaction, triumph, turn, undertaking,
   unraveling, unriddling, unscrambling, unspinning, untangling,
   untwisting, unweaving, upshot, victory, work, working, working-out,
   works