Sixth sense tells where knowledge is to be sought (9)
I believe the answer is:
intuition
'sixth sense' is the definition.
(both can mean an unconscious instinct)
'tells where knowledge is to be sought' is the wordplay.
I cannot really understand how this works, but
'knowledge' could be 'intuit' (I have seen 'instinctive knowledge' mean 'intuit' so perhaps 'knowledge' could also mean 'intuit') and 'intuit' is located in the answer.
The remaining letters 'ion' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for intuition that I've seen before include "Instinct" , "Gut feeling" , "Ability to understand immediately" , "Suspicion" , "Unconscious understanding" .)