Somewhat horrendous death (3)
I believe the answer is:
end
'death' is the definition.
(synonyms)
'somewhat horrendous' is the wordplay.
'somewhat' says the answer is hidden in the clue.
'END' is hidden in the letters of 'horrendous'.
(Other definitions for end that I've seen before include "Cesation, conclusion" , "Intention" , "Exterminate - object" , "Time to break-up (3,2,4) - See 12" , "American footballer" .)