Rejected role as provincial governor once (6)
I believe the answer is:
satrap
'provincial governor once' is the definition.
I can't judge whether this definition defines the answer.
'rejected role as' is the wordplay.
'rejected' is a reversal indicator.
'role' becomes 'part' (eg a part or role in a film).
'part'+'as'='partas'
'partas' reversed gives 'SATRAP'.
Can you help me to learn more?
(Other definitions for satrap that I've seen before include "local ruler" , "Persian provincial governor" , "Persian governor of old; small-time dictator" , "Old Persian ruler" , "Old head" .)