Breaking rules initially in running ashore (9)
I believe the answer is:
breaching
'breaking' is the definition.
('breach' can be a synonym of 'break')
'rules initially in running ashore' is the wordplay.
'initially' indicates taking the first letters.
'in' indicates putting letters inside.
'running ashore' becomes 'beaching'.
The initial letter of 'rules' is 'r'.
'r' put within 'beaching' is 'BREACHING'.
(Other definitions for breaching that I've seen before include "Breaking or failing to observe a law" , "Breaking a rule or law" , "Breakers are" , "Transgressing, rules say" .)