Mythological lyrist (5)
I believe the answer is:
erato
'mythological lyrist' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for erato that I've seen before include "One of nine" , "Who may have inspired poetry" , "Source of poetic inspiration" , "Poetic Muse ; eighteen (anag.)" , "Inspiring female" .)