Bad English criminal turning criminal (7)
I believe the answer is:
illegal
'criminal' is the definition.
(similar in meaning)
'bad english criminal turning' is the wordplay.
'bad' becomes 'ill' (similar in meaning).
'english' becomes 'e' (abbreviation).
'criminal' becomes 'lag' (I've seen this in other clues).
'turning' is a reversal indicator.
'lag' in reverse letter order is 'gal'.
'ill'+'e'+'gal'='ILLEGAL'
(Other definitions for illegal that I've seen before include "Wrong" , "Criminal, illicit" , "Against the rules" , "Unlawful" , "Contraband" .)