Sailor to achieve his aim (6)
I believe the answer is:
target
'his aim' is the definition.
'target' can be an answer for 'aim' (both can mean a goal or purpose). I am not sure about the 'his' bit.
'sailor to achieve' is the wordplay.
'sailor' becomes 'tar' (term for a sailor).
'to achieve' becomes 'get' (I've seen this in another clue).
'tar'+'get'='TARGET'
Can you help me to learn more?
(Other definitions for target that I've seen before include "aunt Sally" , "Aim of an attack" , "A result to aim at" , "What's aimed at" , "purpose" .)