The Collaborative International Dictionary of English v.0.48:

Commitment \Com*mit"ment\, n.
   1. The act of committing, or putting in charge, keeping, or
      trust; consignment; esp., the act of committing to prison.
      [1913 Webster]

            They were glad to compound for his bare commitment
            to the Tower, whence he was within few days
            enlarged.                             --Clarendon.
      [1913 Webster]

   2. A warrant or order for the imprisonment of a person; --
      more frequently termed a mittimus.
      [1913 Webster]

   3. The act of referring or intrusting to a committee for
      consideration and report; as, the commitment of a petition
      or a bill.
      [1913 Webster]

   4. A doing, or perpetration, in a bad sense, as of a crime or
      blunder; commission.
      [1913 Webster]

   5. The act of pledging or engaging; the act of exposing,
      endangering, or compromising; also, the state of being
      pledged or engaged. --Hamilton.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

201 Moby Thesaurus words for "commitment":
   abandon, activity, affair, agency, agentship, agreement,
   allegiance, altruism, ardency, ardor, assigned task, assignment,
   attempt, authority, authorization, bounden duty, brevet, burden,
   business, call of duty, campaign, care, cause, charge,
   commendation, commission, commissioning, committal, committedness,
   consecration, consignment, constancy, contract, crusade, cure,
   deal, decidedness, decision, decisiveness, dedication, deference,
   definiteness, delegated authority, delegation, deputation,
   determinateness, determination, determinedness, devoir, devolution,
   devolvement, devotedness, devotion, devoutness, disinterest,
   disinterestedness, drive, duties and responsibilities, duty,
   earnestness, effort, embassy, empowerment, enfeoffment, engagement,
   enterprise, entrusting, entrustment, errand, ethics, executorship,
   exequatur, factorship, faith, faithfulness, fastness, fealty,
   fervency, fervidness, fervor, fidelity, fire, firmness, full power,
   great cause, hallowing, heartiness, heat, heatedness, homage,
   humility, impassionedness, imperative, infeodation, infeudation,
   intensity, intentness, interest, issue, jurisdiction, legation,
   license, lieutenancy, lifework, line of duty, loyalty, mandate,
   mass movement, mission, mittimus, modesty, movement, must, need,
   obligation, obstinacy, office, onus, operation, ordainment,
   ordination, ought, passion, passionateness, perseverance,
   persistence, place, plan, plenipotentiary power, power of attorney,
   power to act, preengagement, principle, procuration, program,
   project, proposition, proxy, purpose, purposefulness, purview,
   reason for being, recognizance, recommitment, regency, regentship,
   relegation, relentlessness, remand, remanding, resoluteness,
   resolution, resolve, resolvedness, respect, responsibility, right,
   sacrifice, self-abasement, self-abnegation, self-denial,
   self-devotion, self-effacement, self-forgetfulness,
   self-immolation, self-imposed duty, self-neglect,
   self-neglectfulness, self-renouncement, self-sacrifice,
   self-subjection, self-will, selflessness, seriousness, sincerity,
   single-mindedness, spirit, staunchness, steadfastness, task,
   tenacity, total commitment, tried-and-trueness, triedness,
   trueness, trust, trusteeship, unacquisitiveness, understanding,
   undertaking, unpossessiveness, unselfishness, vehemence, venture,
   verbal agreement, vicarious authority, warmth, warrant, will, work,
   zeal