Racier, it breaks rules (8)
I believe the answer is:
criteria
'rules' is the definition.
('criterion' can be a synonym of 'rule')
'racier it breaks' is the wordplay.
'breaks' indicates anagramming the letters.
'racier'+'it'='racierit'
'racierit' is an anagram of 'CRITERIA'.
(Other definitions for criteria that I've seen before include "Principles for decision" , "Standards of judgement to be met" , "Standards, yardsticks" , "Standards on which to base judgments" , "Standards by which things measured" .)