The Collaborative International Dictionary of English v.0.48:

anoxia \an`ox"i*a\ ([a^]n*[o^]ks"[i^]*[.a]), n. [NL.; Gr. 'an
   priv. + oxygen.]
   1. (Med.) A physiological state in which insufficient oxygen
      reaches the tissues of the body, especially when of
      sufficient severity to cause permanent damage; severe
      hypoxia.
      [Webster 1913 Suppl. + AS]

   2. (Med) Total lack of oxygen.
      [AS]

WordNet (r) 3.0 (2006):

anoxia
    n 1: severe hypoxia; absence of oxygen in inspired gases or in
         arterial blood or in the tissues

Moby Thesaurus II by Grady Ward, 1.0:

98 Moby Thesaurus words for "anoxia":
   Minamata disease, abscess, ague, altitude sickness, anemia,
   ankylosis, anoxemia, anoxic anoxia, anthrax, apnea, asphyxiation,
   asthma, ataxia, atrophy, backache, black lung, blackout, bleeding,
   blennorhea, cachexia, cachexy, caisson disease, chilblain, chill,
   chills, colic, constipation, convulsion, coughing, cyanosis,
   decompression sickness, diarrhea, dizziness, dropsy, dysentery,
   dyspepsia, dyspnea, edema, emaciation, fainting, fatigue, fever,
   fibrillation, flux, frostbite, grayout, growth, hemorrhage,
   high blood pressure, hydrops, hypertension, hypotension, icterus,
   immersion foot, indigestion, inflammation, insomnia, itai, itching,
   jaundice, jet lag, labored breathing, lead poisoning,
   low blood pressure, lumbago, marasmus, mercury poisoning,
   motion sickness, nasal discharge, nausea, necrosis, pain,
   paralysis, pneumoconiosis, pressure suit, pruritus,
   radiation sickness, radionecrosis, rash, red-out, rheum, sclerosis,
   seizure, shock, skin eruption, sneezing, sore, spasm, sunstroke,
   tabes, tachycardia, the bends, trench foot, tumor, upset stomach,
   vertigo, vomiting, wasting