Lone Ranger's sidekick (5)
I believe the answer is:
tonto
'lone ranger's sidekick' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tonto that I've seen before include "Western companion" , "Lone Ranger and - -" , "The Lone Ranger's sidekick" , "The Lone Ranger's companion" , "Faithful companion" .)