Break a rule -- get control (8)
I believe the answer is:
regulate
'control' is the definition.
(thesaurus)
'break a rule get' is the wordplay.
'break' is an anagram indicator.
'a'+'rule'+'get'='aruleget'
'aruleget' anagrammed gives 'REGULATE'.
(Other definitions for regulate that I've seen before include "Control or direct by means of rules and procedures" , "Bring order" , "Ate gruel (anag.)" , "ADjust, fix" , "Ensure conformity with the rules" .)