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.
      [1913 Webster]

            This chafed the boar; his nostrils flames expire.
                                                  --Dryden.
      [1913 Webster]

   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.
      [1913 Webster]

            The expiring of cold out of the inward parts of the
            earth in winter.                      --Bacon.
      [1913 Webster]

   3. To emit; to give out. [Obs.] --Dryden.
      [1913 Webster]

   4. To bring to a close; to terminate. [Obs.]
      [1913 Webster]

            Expire the term
            Of a despised life.                   --Shak.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Expire \Ex*pire"\, v. i.
   1. To emit the breath.
      [1913 Webster]

   2. To emit the last breath; to breathe out the life; to die;
      as, to expire calmly; to expire in agony.
      [1913 Webster]

   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.
      [1913 Webster]

   4. To burst forth; to fly out with a blast. [Obs.] "The
      ponderous ball expires." --Dryden.
      [1913 Webster]

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]

Moby Thesaurus II by Grady Ward, 1.0:

131 Moby Thesaurus words for "expire":
   advance, be all over, be annihilated, be destroyed, be done for,
   be lost, be no more, be wiped out, become extinct, become void,
   blow, blow over, breathe, breathe hard, breathe in, breathe out,
   cease, cease to be, cease to exist, cease to live, close,
   come to naught, come to nothing, conclude, conk, conk out,
   continue, cough, croak, decease, demise, depart, depart this life,
   die, die away, die out, disappear, discontinue, dissolve, elapse,
   emit, end, endure, evacuate, evaporate, exhale, exhaust, expel,
   fade, fade away, fade out, fall, fall asleep, finish, flee, flit,
   flow, flow on, fly, fume, gasp, give off, give out, give vent to,
   glide, go, go by, go on, go out, gulp, hack, have it,
   have its time, hiccup, huff, inhale, inspire, kick off, lapse,
   last, leave no trace, let out, melt away, open the floodgates,
   open the sluices, pant, part, pass, pass away, pass by, pass on,
   pass over, peg out, perish, peter out, press on, proceed, puff,
   put off mortality, quit this world, reek, respire, return to dust,
   roll on, run, run its course, run on, run out, sigh, slide, slip,
   smoke, sneeze, sniff, sniffle, snore, snort, snuff, snuffle, steam,
   stop breathing, succumb, terminate, throw off, up and die, vanish,
   vapor, wear away, wear off, wheeze, yield the ghost