Traitors heading west act the hero (4)
I believe the answer is:
star
'act the hero' is the definition.
'star' can be an answer for 'act' (thesaurus). I'm unsure of the 'the hero' bit.
'traitors heading west' is the wordplay.
'traitors' becomes 'rats' (rat can mean a traitor).
'heading west' says the letters should be written in reverse.
'rats' written backwards gives 'STAR'.
Can you help me to learn more?
(Other definitions for star that I've seen before include "Sign of a leading performer" , "Leading character" , "Heavenly body - leading actress?" , "Polaris, possibly" , "Famous performer" .)