Inspiration sources (5)
I believe the answer is:
muses
'inspiration sources' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for muses that I've seen before include "Thinks" , "Nine goddesses who presided over learning and the arts" , "Ponders like nine goddesses of Roman myth" , "Ponders like Greek goddesses" , "Nine goddesses, inspirations for artists" .)