Check about golf rule (5)
I believe the answer is:
reign
'rule' is the definition.
(reign is a kind of rule)
'check about golf' is the wordplay.
'check' becomes 'rein' (both can mean to control or limit).
'about' indicates putting letters inside.
'golf' becomes 'g' (phonetic alphabet: alpha, bravo, charlie etc.).
'rein' enclosing 'g' is 'REIGN'.
(Other definitions for reign that I've seen before include "time in power" , "Monarch's period" , "Predominance" , "Period on the throne" , "Occupy the throne" .)