Corporation curtailed alarm (4)
I believe the answer is:
bell
'alarm' is the definition.
(thesaurus)
'corporation curtailed' is the wordplay.
'corporation' becomes 'belly' ('belly' can be a synonym of 'corporation').
'curtailed' means to remove the last letter.
'belly' with its last letter removed is 'BELL'.
(Other definitions for bell that I've seen before include "Tinkler" , "kind of curve" , "Chime" , "bicycle accessory" , "pen name" .)