Same turning, indicate left (9)
I believe the answer is:
Here is my best explanation:
'same' is the definition.
('identical' can be similar in meaning to 'same')
'turning indicate left' is the subsidiary indication.
'turning' indicates anagramming the letters.
'left' becomes 'l' (common abbreviation).
'indicate' anagrammed gives 'identica'.
(Other definitions for identical that I've seen before include "Like two peas in a pod", "Matching", "Duplicate", "as B and B", "Not any different", "Aid client to be the very same", "showing no change", "All the same", "Exactly alike, the same in every detail" and "Just the same".)