Or hypoxia; In biology, deprivation of oxygen, a condition that rapidly leads to collapse or death, unless immediately reversed.
Severe hypoxia; absence of oxygen in inspired gases or in arterial blood or in the tissues.
Deficiency of oxygen especially severe; condition due to this, especially in flying at great heights.

A very strong drive resulting from oxygen deficiency in bodily tissues (short of anoxia).
Shortage of oxygen in the tissues. See also anoxia.