The Collaborative International Dictionary of English v.0.48:

Expire \Ex*pire"\, v. t. [imp. & p. p. Expired; p. pr & vb. n.
   Expiring.] [L. expirare, exspirare, expiratum, exspiratum;
   ex out + spirare to breathe: cf. F. expirer. See Spirit.]
   1. To breathe out; to emit from the lungs; to throw out from
      the mouth or nostrils in the process of respiration; --
      opposed to inspire.
      [1913 Webster]

            Anatomy exhibits the lungs in a continual motion of
            inspiring and expiring air.           --Harvey.
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            This chafed the boar; his nostrils flames expire.
                                                  --Dryden.
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   2. To give forth insensibly or gently, as a fluid or vapor;
      to emit in minute particles; to exhale; as, the earth
      expires a damp vapor; plants expire odors.
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            The expiring of cold out of the inward parts of the
            earth in winter.                      --Bacon.
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   3. To emit; to give out. [Obs.] --Dryden.
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   4. To bring to a close; to terminate. [Obs.]
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            Expire the term
            Of a despised life.                   --Shak.
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The Collaborative International Dictionary of English v.0.48:

expired \expired\ adj.
   having come to an end or become void after passage of a
   period of time; as, an expired passport; caught driving with
   an expired license. Opposite of unexpired.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

expired
    adj 1: having come to an end or become void after passage of a
           period of time; "an expired passport"; "caught driving
           with an expired license" [ant: unexpired]