Sulk, brood (4)
I believe the answer is:
mope
This clue is a double definition.
'sulk' is the first definition.
(I've seen this before)
'brood' is the second definition.
(I've seen this in another clue)
(Other definitions for mope that I've seen before include "Hang about moodily over poem" , "Brood over a poem" , "Be listless over poem" , "Poem (anag.)" , "Hang around being miserable" .)