Inspiration from singer at opera (5)
I believe the answer is:
erato
'inspiration' is the definition.
(I've seen this before)
'from singer at opera' is the wordplay.
'from' says the answer is hidden in the clue.
'ERATO' can be found hidden inside 'singer at opera'.
(Other definitions for erato that I've seen before include "Inspiring female" , "poetical inspiration" , "One of nine" , "Greek muse of lyric and love poetry" , "Muse of 11 and 23" .)