Lacking oxygen; without oxygen; not oxygenated.
The term anoxic is used to describe a condition or an environment that lacks oxygen, as anoxic water which is devoid of oxygen, and anoxic event, which is when the oceans become completely depleted of oxygen below the surface levels. According to geologic record, anoxic events happened in the past and may have caused mass extinctions.
Compare: hypoxic, anoxic, hyperoxic.
See also: anaerobic.