[1] : The Collaborative International Dictionary of English v.0.48

carelessness \care"lessness\, n.
   the quality or state of being careless; heedlessness;
   negligence; inattention.
   1913 webster

[2] : WordNet (r) 2.0

carelessness
     n 1: the quality of not being careful or taking pains ant: carefulness
     2: failure to act with the prudence that a reasonable person
        would exercise under the same circumstances syn: negligence,
         neglect, nonperformance
see also:
carefulness negligence neglect nonperformance 

[3] : Moby Thesaurus II by Grady Ward, 1.0

160 moby thesaurus words for "carelessness":
   abandon, absentmindedness, accidia, acedia, aloofness, apathy,
   ataraxia, ataraxy, blowziness, blunderheadedness, blundering,
   boggling, boredom, botchery, botching, bungling, caprice,
   careless abandon, casualness, chintziness, cursoriness,
   desperateness, detachment, devil-may-careness, disinterest,
   disinterestedness, dispassion, disregard, disregardfulness,
   distraction, dowdiness, easiness, easygoingness, flightiness,
   flippancy, forgetfulness, frivolousness, frowziness, frumpishness,
   fumbling, furiousness, giddiness, grubbiness, haste, hastiness,
   heedlessness, hotheadedness, hurriedness, impassiveness,
   impassivity, impetuosity, impetuousness, impotence, imprecision,
   inadvertence, inadvertency, inattention, inattentiveness,
   inconsiderateness, inconsideration, incuriosity, incuriousness,
   indifference, indifferentism, indifferentness, indiscrimination,
   inexcitability, inobservance, insouciance, intellectual inertia,
   lack of affect, lack of foresight, lack of interest,
   lackadaisicalness, laxity, laxness, laziness, leniency, levity,
   lightmindedness, listlessness, looseness, loosening, messiness,
   mindlessness, muffing, negligence, nonchalance, nonobservance,
   oblivion, obliviousness, offhandedness, overeagerness,
   overenthusiasm, overindulgence, overpermissiveness,
   overzealousness, perfunctoriness, permissiveness, pococurantism,
   precipitance, precipitancy, precipitateness, precipitation,
   precipitousness, recklessness, regardlessness, relaxation,
   relaxedness, remissness, seediness, shabbiness, shallowness,
   shoddiness, slackness, slatternliness, slipshodness, sloppiness,
   sloth, slovenliness, slovenry, sluttishness, softness, sordidness,
   sprezzatura, squalidness, squalor, stolidity, superficiality,
   tackiness, tactlessness, tawdriness, thoughtlessness,
   too many cooks, unalertness, unanxiousness, unawareness, unconcern,
   unconsciousness, unheedfulness, uninquisitiveness, unintentiveness,
   uninterestedness, unmindfulness, unneatness, unobservance,
   unpreparedness, unreadiness, unrestraint, unsolicitousness,
   unsolicitude, unthinkingness, unthoughtfulness, untidiness,
   unwariness, unwatchfulness, wantonness, weakness, wildness,
   withdrawal

Carelessness >> C Words
Carelessness, definition of term: Carelessness
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