Are back to muse (5)
I believe the answer is:
erato
'muse' is the definition.
(Erato is an example)
'are back to' is the wordplay.
'back' shows that the letters should be reversed in order.
'are' written backwards gives 'era'.
'era'+'to'='ERATO'
(Other definitions for erato that I've seen before include "Muse of lyric poetry and mime" , "One of the Muses" , "verses she inspired" , "goddess" , "poetical inspiration" .)