Decease (5)
I believe the answer is:
death
'decease' is the definition.
(I know that decease can be written as death)
This is the entire clue.
(Other definitions for death that I've seen before include ""The last enemy"" , "Hated (anag) - curtains (informal)" , "Extinction" , "Hated (anag) -- expiry" , "End of life" .)