Destroy object (3)
I believe the answer is:
end
This clue is a double definition.
'destroy' is the first definition.
(thesaurus)
'object' is the second definition.
(end is a kind of object)
(Other definitions for end that I've seen before include "'Finish, cease (3)'" , "Conclusion, finish" , "Culmination" , "Aim or goal" , "American footballer" .)