Solid part of orange juice (4)
I believe the answer is:
pulp
'solid part of orange juice' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for pulp that I've seen before include "Soft fleshy part of a fruit" , "Mush" , "Soft structureless mass - type of fiction" , "Crush" , "Nonsense" .)