Counsel's not primarily bad fault (6)
I believe the answer is:
advice
'counsel's' is the definition.
(I've seen this before)
'not primarily bad fault' is the wordplay.
'not primarily' means to remove the first letter.
'fault' becomes 'vice' (I've seen this before).
'bad' with its first letter taken off is 'ad'.
'ad'+'vice'='ADVICE'
(Other definitions for advice that I've seen before include "Intelligence" , "Counsel given" , "tip" , "What lawyer offers" , "Recommendation for a course of action" .)