Frequently (in poetry) (3)
I believe the answer is:
oft
'frequently in poetry' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for oft that I've seen before include "Many times, of old" , "Many a time to the poet." , "Many times (archaic)" , "''... in the stilly night'' (Moore melody)" , "Quite frequently, according to the poet" .)