Aim, purpose (9)
I believe the answer is:
intention
This clue is a double definition.
'aim' is the first definition.
(I know that aim can be written as intention)
'purpose' is the second definition.
(I know that purpose can be written as intention)
(Other definitions for intention that I've seen before include "Plan, purpose" , "goal" , "Design" , "Aim, plan" , "Aim, objective" .)