Puts to death (8)
I believe the answer is:
executes
'puts to death' is the definition.
('execute' can be a synonym of 'put to death')
This is all the clue.
(Other definitions for executes that I've seen before include "Carries out and puts to death" , "Carries out something" , "Carries out and legally kills" , "Does away with" , "Carries out or inflicts capital punishment" .)