Stagnant (8)
I believe the answer is:
moribund
'stagnant' is the definition.
(I know that stagnant can be written as moribund)
This is all the clue.
(Other definitions for moribund that I've seen before include "Decaying" , "At the point of death" , "In terminal decline" , "Near to death" , "Lifeless" .)