Bishop smuggled cases of grain (4)
I believe the answer is:
bran
'cases of grain' is the definition.
'bran' can be an answer for 'grain' (thesaurus). I'm not certain of the 'cases of' bit.
'bishop smuggled' is the wordplay.
'bishop' becomes 'B' (abbreviation for bishop in chess).
'smuggled' becomes 'ran' (to run something is to smuggle it).
'b'+'ran'='BRAN'
Can you help me to learn more?
(Other definitions for bran that I've seen before include "Food from the husks of cereal grains" , "Refuse from grain" , "Husks of cereal grain" , "Coarse meal for horse food" , "Fibre cereal" .)