Vegetative state (4)
I believe the answer is:
coma
'vegetative state' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for coma that I've seen before include "State of deep (often prolonged) unconsciousness" , "Deep trance" , "Long period of unconsciousness" , "Unconsciousness from which person cannot be aroused" , "Stupor" .)