Offence announced to test sentencing rules? (6)
I believe the answer is:
syntax
'sentencing rules?' is the definition.
(rules for writing sentences or clauses)
'offence announced to test' is the wordplay.
'offence' becomes 'sin' (a sin is an offence or transgression).
'announced' shows a homophone (sound like).
'to test' becomes 'tax'.
'sin' sounds like 'syn'.
'syn'+'tax'='SYNTAX'
(Other definitions for syntax that I've seen before include "Verbal order" , "Rules for sentence construction" , "Rules governing formation of sentences and phrases" , "The rules governing the arrangement of words in sentences etc" , "The rules governing the arranging of words" .)