Bossy's chew (3)
I believe the answer is:
cud
'bossy's chew' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for cud that I've seen before include "Re-chewed food of a ruminant" , "it's still in the cow" , "Cows chew it" , "Wad of something chewable" , "Ruminant's regurgitated food" .)