Obi-Wan's portrayer (4)
I believe the answer is:
alec
'obi-wan's portrayer' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for alec that I've seen before include "Boy's name (a smart one?)" , "Actor Guinness is smart" , "Smart boy?" , "Guinness (a smart lad?)" , "Smart man?" .)