Sweetheart surrounded by cleaning equipment sulks (5)
I believe the answer is:
'sulks' is the definition.
'sweetheart surrounded by cleaning equipment' is the wordplay.
'sweetheart' becomes 'e' (the heart/centre of 'sweet').
'surrounded by' indicates putting letters inside.
'cleaning equipment' becomes 'mops'.
'e' placed within 'mops' is 'MOPES'.
(Other definitions for mopes that I've seen before include "is miserable" , "Hangs around apathetically" , "Feels dejected" , "Moons around" , "Broods about poems" .)