Ask about a prior storyteller (5)
I believe the answer is:
aesop
'storyteller' is the definition.
(Aesop is an example)
'ask about a prior' is the wordplay.
'ask' becomes 'pose' (synonyms).
'about' shows that the letters should be reversed in order.
'prior' is a charade indicator (letters next to each other).
'pose' written backwards gives 'esop'.
'esop' after 'a' is 'AESOP'.
(Other definitions for aesop that I've seen before include "So ape the writer of fables" , "Greek author, famous for his fables" , "his writings were fabulous" , "Greek author of fables (c 620-560 BC)" , "Greek father of fables" .)