The Collaborative International Dictionary of English v.0.48:

d'egag'e \d['e]`ga`g['e]"\, a. [F., p. p. of d['e]gager to
   disengage. See De-, 1st Gage, and cf. Disgage.]
   Unconstrained; easy; free. --Vanbrugh.

         A graceful and d['e]gag['e] manner.      --Poe.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

degage
    adj 1: free and relaxed in manner; "rather degage after the
           nervousness he had shown at dinner"- Edmund Wilson
    2: showing lack of emotional involvement; "adopted a degage pose
       on the arm of the easy chair"- J.S.Perelman; "she may be
       detached or even unfeeling but at least she's not
       hypocritically effusive"; "an uninvolved bystander" [syn:
       degage, detached, uninvolved]

Moby Thesaurus II by Grady Ward, 1.0:

68 Moby Thesaurus words for "degage":
   Bohemian, affable, airy, blase, breezy, careless, casual, common,
   cordial, cursory, devil-may-care, disregardant, disregardful, easy,
   easygoing, familiar, flippant, folksy, forgetful, free and easy,
   gracious, haymish, heedless, homely, homey, inconsiderate,
   indifferent, informal, insouciant, irregular, lackadaisical, lazy,
   loose, low-pressure, natural, nonchalant, oblivious, offhand,
   offhanded, perfunctory, plain, reckless, regardless, relaxed,
   respectless, simple, sociable, tactless, thoughtless, unaffected,
   unassuming, unceremonious, unconcerned, unconstrained,
   unconventional, undiplomatic, unfussy, unheedful, unheeding,
   unmindful, unofficial, unprepared, unready, unreserved,
   unsolicitous, unstudied, untactful, unthinking