Something for breakfast, a dead duck! (5)
I believe the answer is:
toast
'something for breakfast' is the definition.
'a dead duck' is the wordplay.
I cannot really understand how this works, but
'a' is within the answer.
'duck' could be 'o' (resembles zero - 'duck' in cricket) and 'o' is found within the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for toast that I've seen before include "Drink the health of - brown bread!" , "Food (that one can drink!)" , "making this pledge?" , "Drink one's health" , "Breakfast item served in rounds" .)