Muse of lyric poetry (5)
I believe the answer is:
erato
'muse of lyric poetry' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for erato that I've seen before include "Clio's sister" , "poetical inspiration" , "Source of artistic inspiration" , "One inspiring" , "Muse of 11 and 23" .)