Instinctive knowledge (9)
I believe the answer is:
intuition
'instinctive knowledge' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for intuition that I've seen before include "An indefinable knowledge" , "Unjustified belief" , "Instinct" , "an instinctive thing" , "Unconscious understanding" .)