The conclusion of public spending
I believe the answer is:
end
'the conclusion' is the definition.
(something's conclusion is its end)
'of public spending' is the wordplay.
'of' indicates a hidden word.
'END' can be found hidden inside 'public spending'.
(Other definitions for end that I've seen before include "Terminate in den" , "Aim; terminate" , "result" , "Conclude" , "death" .)