The Collaborative International Dictionary of English v.0.48:

Withdrawal \With*draw"al\, n.
   The act of withdrawing; withdrawment; retreat; retraction.
   --Fielding.
   [1913 Webster]

WordNet (r) 3.0 (2006):

withdrawal
    n 1: a retraction of a previously held position [syn:
         withdrawal, backdown, climb-down]
    2: the act of taking out money or other capital
    3: the act of withdrawing; "the withdrawal of French troops from
       Vietnam"
    4: avoiding emotional involvement [syn: withdrawal,
       detachment]
    5: the act of withdrawing blood, tumors, etc.; "the nurse was
       expert at the withdrawal of blood"
    6: the act of ceasing to participate in an activity
    7: a method of birth control in which coitus is initiated but
       the penis is deliberately withdrawn before ejaculation [syn:
       coitus interruptus, withdrawal method, withdrawal,
       pulling out, onanism]
    8: formal separation from an alliance or federation [syn:
       secession, withdrawal]
    9: the termination of drug taking [syn: withdrawal, drug
       withdrawal]

Moby Thesaurus II by Grady Ward, 1.0:

379 Moby Thesaurus words for "withdrawal":
   Jim Crow, abandonment, abdication, abjuration, abjurement,
   abolishment, abolition, abrogation, absentation, abstraction,
   abulia, agreement to disagree, alienation, aloneness, aloofness,
   anesthesia, annulment, anxiety, anxiety equivalent, anxiety state,
   apartheid, apartness, apathy, apostasy, autism, autistic thinking,
   avoidance mechanism, avulsion, backwardness, bashfulness,
   blame-shifting, blankness, boredom, cancel, canceling,
   cancellation, carelessness, cassation, casting away, catatonia,
   catatonic stupor, celibacy, cessation, chill, chilliness,
   clearance, cold blood, cold heart, coldheartedness, coldness,
   compensation, compulsion, constraint, coolness, counter-culture,
   countermand, counterorder, cutting out, deadpan, decampment,
   decompensation, defeasance, defense mechanism, dejection,
   demission, denial, departure, deportation, deposal, depression,
   deracination, dereism, dereistic thinking, desuetude, detachment,
   difference, disaccord, disagreement, disapprobation, disapproval,
   disarticulation, disassociation, disavowal, discard, disclaimer,
   disclamation, disconnectedness, disconnection, discontinuity,
   discreetness, discretion, disengagement, disentanglement,
   disinterest, disinterestedness, disjointing, disjunction,
   dislocation, disowning, disownment, disparity, dispassion,
   dispassionateness, displacement, disposal, disposition,
   dissatisfaction, dissension, dissent, dissentience, dissidence,
   dissociation, distance, disunion, disuse, diversity, division,
   divorce, divorcement, drawing, drawing out, dredging, drilling,
   dropping out, dullness, egress, ejection, elation, elimination,
   emeritus status, emotional deadness, emotional insulation,
   emotionalism, emotionlessness, enucleation, eradication, escape,
   escape into fantasy, escape mechanism, escapism, euphoria,
   evacuation, evolvement, evulsion, excavation, excision, exile,
   exit, exodus, expatriation, expression, expressionlessness,
   expulsion, exsection, extirpation, extraction, extrication,
   fallback, fantasizing, fantasy, flight, folie du doute,
   forced resignation, forsaking, forswearing, frigidity, frostiness,
   getaway, going, guardedness, heartlessness, heedlessness, hegira,
   hypochondria, hysteria, hysterics, iciness, immovability,
   impassibility, impassiveness, impassivity, impersonality,
   inaccessibility, incoherence, incuriosity, incuriousness,
   indifference, indifferentism, indifferentness, inexcitability,
   insensibility, insouciance, intellectual inertia, introversion,
   invalidation, isolation, isolationism, jettison, jettisoning,
   keeping apart, lack of affect, lack of feeling, lack of interest,
   lack of touch, leaving, lethargy, liquidation, listlessness,
   loneliness, loneness, lonesomeness, luxation, mania, melancholia,
   mental distress, mining, minority opinion, modesty, moving apart,
   negativism, nonagreement, nonassent, nonconcurrence, nonconformity,
   nonconsent, nullification, objectivity, obsession, obtuseness,
   opposition, ostracism, outlawing, outlawry, overcompensation,
   palinode, palinody, parting, partition, passing, passionlessness,
   pathological indecisiveness, poker face, preoccupation,
   pressing out, privacy, privatism, privatization, projection,
   psychalgia, psychomotor disturbance, psychotaxis, pullback,
   pulling, pulling out, pullout, purge, quarantine, quarrying,
   rationalization, recall, recantation, recedence, receding, recess,
   recession, reclusion, reculade, recusance, recusancy,
   regardlessness, rejection, relinquishment, remoteness, removal,
   renege, reneging, renouncement, renunciation, repeal, repression,
   repudiation, rescinding, rescindment, rescission, reserve,
   reservedness, resignation, resistance, restraint, reticence,
   reticency, retiral, retirement, retractation, retractility,
   retraction, retreat, retrocedence, reversal, revocation, revoke,
   revokement, riddance, ripping out, rustication, secession,
   seclusion, secrecy, segmentation, segregation, self-absorption,
   separateness, separation, separatism, sequestration, setting aside,
   severance, single blessedness, sociological adjustive reactions,
   solitariness, solitude, soullessness, spiritlessness,
   splendid isolation, squeezing out, standoffishness, stolidity,
   straight face, stupor, subdivision, sublimation, substitution,
   subtraction, superannuation, suppression, suspension,
   throwing overboard, tic, twitching, unaffability,
   unapproachability, unconcern, uncongeniality, undemonstrativeness,
   underground, unemotionalism, unexcitability, unexpansiveness,
   unfeeling, unfeelingness, unimpressibility, unimpressionableness,
   uninquisitiveness, uninterestedness, unmindfulness,
   unpassionateness, unresponsiveness, unrooting, unsaying,
   unsusceptibility, unsympatheticness, untouchability, uprooting,
   vacation, vacatur, variance, voidance, voiding,
   voluntary resignation, waiver, waiving, walkout,
   wish-fulfillment fantasy, wishful thinking, withdrawment,
   withdrawnness, wresting out, write-off, zoning