Some toast stunning defeat in study (7)
I believe the answer is:
crouton
'some toast stunning' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'defeat in study' is the wordplay.
'defeat' becomes 'rout' (rout is a kind of defeat).
'in' means one lot of letters goes inside another.
'study' becomes 'con' (conning is a kind of studying).
'rout' put into 'con' is 'CROUTON'.
Can you help me to learn more?
(Other definitions for crouton that I've seen before include "Small cube of toasted bread" , "One might be in the soup" , "little bit of bread" , "Fried bread as garnish" , "Small piece of toasted or fried bread served in soup" .)