Rod left in rage (6)
I believe the answer is:
angler
'rod' is the definition.
(rod can mean an angler)
'left in rage' is the wordplay.
'left' becomes 'l' (common abbreviation).
'in' indicates putting letters inside.
'rage' becomes 'anger' (I've seen this in other clues).
'l' inserted into 'anger' is 'ANGLER'.
(Other definitions for angler that I've seen before include "I may do casting" , "A rod and line fisherman" , "A rod-and-line fisherman" , "person hoping to catch fish" , "Strait; -- of Lochalsh" .)