Cognitive (6)
I believe the answer is:
mental
'cognitive' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for mental that I've seen before include "Lament (anag) - of the mind" , "Done in the mind" , "off trolley" , "Pertaining to the mind" , "Light allowing vehicles to turn while ahead is red" .)