Shortly, in poems (4)
I believe the answer is:
anon
'shortly in poems' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for anon that I've seen before include "Presently - unattributed" , "Of unknown identity, in short" , "Soon - unknown author (abbr)" , "Incognito (abbrev)" , "Immediately" .)