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.
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            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:

Expire \Ex*pire"\, v. i.
   1. To emit the breath.
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   2. To emit the last breath; to breathe out the life; to die;
      as, to expire calmly; to expire in agony.
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   3. To come to an end; to cease; to terminate; to perish; to
      become extinct; as, the flame expired; his lease expires
      to-day; the month expired on Saturday.
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   4. To burst forth; to fly out with a blast. [Obs.] "The
      ponderous ball expires." --Dryden.
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WordNet (r) 3.0 (2006):

expire
    v 1: lose validity; "My passports expired last month" [syn: run
         out, expire]
    2: pass from physical life and lose all bodily attributes and
       functions necessary to sustain life; "She died from cancer";
       "The children perished in the fire"; "The patient went
       peacefully"; "The old guy kicked the bucket at the age of
       102" [syn: die, decease, perish, go, exit, pass
       away, expire, pass, kick the bucket, cash in one's
       chips, buy the farm, conk, give-up the ghost, drop
       dead, pop off, choke, croak, snuff it] [ant: be
       born]
    3: expel air; "Exhale when you lift the weight" [syn: exhale,
       expire, breathe out] [ant: breathe in, inhale,
       inspire]