Be sentimental in Oslo, perhaps (4)
I believe the answer is:
slop
'be sentimental' is the definition.
I can't judge whether this defines the answer.
'in oslo perhaps' is the wordplay.
'in' indicates the answer is hidden within the clue.
'SLOP' is hidden within 'oslo perhaps'.
Can you help me to learn more?
(Other definitions for slop that I've seen before include "Splash" , "discarded > loose garment" , "Bobby" , "Household liquid refuse" , "Liquid refuse, swill" .)