Duck exercise and limit action (9)
I believe the answer is:
operation
'action' is the definition.
(operation is a kind of action)
'duck exercise and limit' is the wordplay.
'duck' becomes 'o' (resembles zero - 'duck' in cricket).
'exercise' becomes 'pe' (Physical Education).
'and' is a charade indicator (letters next to each other).
'limit' becomes 'ration' (rationing is a kind of limiting).
'o'+'pe'+'ration'='OPERATION'
(Other definitions for operation that I've seen before include "Handling" , "Action; process" , "Act of surgery" , "battle" , "working" .)