nonchalance

from WordNet (r) 3.0 (2006)

nonchalance
    n 1: the trait of remaining calm and seeming not to care; a
         casual lack of concern [syn: {nonchalance}, {unconcern},
         {indifference}]

from The Collaborative International Dictionary of English v.0.48

Nonchalance \Non`cha`lance"\, n. [F. See {Nonchalant}.]
   Indifference; carelessness; coolness.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

69 Moby Thesaurus words for "nonchalance":
      accidia, acedia, aloofness, apathy, ataraxia, ataraxy,
      benumbedness, blah, blahs, carelessness, casualness, comatoseness,
      detachment, disinterest, dispassion, disregard, disregardfulness,
      dullness, easygoingness, heartlessness, hebetude, heedlessness,
      hopelessness, inappetence, inattention, incuriosity, indifference,
      indiscrimination, inexcitability, insouciance, lack of affect,
      lack of appetite, lackadaisicalness, languidness, lethargicalness,
      lethargy, listlessness, mindlessness, negligence, numbness,
      offhandedness, passiveness, passivity, phlegm, phlegmaticalness,
      phlegmaticness, plucklessness, pococurantism, recklessness,
      regardlessness, resignation, resignedness, sloth, sluggishness,
      sopor, soporifousness, spiritlessness, spunklessness, stupefaction,
      stupor, supineness, torpidity, torpidness, torpor, unanxiousness,
      unconcern, unmindfulness, unsolicitousness, withdrawnness

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