Concentrating on one's aim (6)
I believe the answer is:
intent
This might be a double definition.
'concentrating' is the first definition.
(I've seen this before)
'one's aim' is the second definition.
'intent' can be an answer for 'aim' (synonyms). I'm not sure about the 'one's' bit.
'on' acts as a link.
Can you help me to learn more?
(Other definitions for intent that I've seen before include "Bent on, determined to" , "Purpose; determined" , "Focused" , "Resolved; purpose" , "'Engrossed, absorbed (6)'" .)