Death by suffocation (8)
I believe the answer is:
asphyxia
'death by suffocation' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for asphyxia that I've seen before include "Suffocation, condition caused by lack of oxygen" , "Death by suffocation" , "It's caused by choking or drowning" , "Oxygen starvation" , "Deprivation of oxygen" .)