Aim shown by largely immaculate model (7)
I believe the answer is:
purpose
'aim' is the definition.
('purpose' can be a synonym of 'aim')
'shown by largely immaculate model' is the wordplay.
'shown by' says to put letters next to each other.
'largely' means to remove the last letter.
'immaculate' becomes 'pure' ('pure' can be a synonym of 'immaculate').
'model' becomes 'pose' ('pose' can be a synonym of 'model'**).
'pure' with its last letter taken off is 'pur'.
'pur' next to 'pose' is 'PURPOSE'.
(Other definitions for purpose that I've seen before include "Resolve, objective" , "Function" , "Reason for existence" , "Will - point" , "End" .)