Start off football downcast, dropping left winger (4)
I believe the answer is:
fowl
'winger' is the definition.
(fowl is a kind of bird)
'start off football downcast dropping left' is the wordplay.
'start off' suggests taking the first letters.
'downcast' becomes 'ow' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'dropping' says to take the initial letters (I've seen 'drop of' mean this).
The initial letter of 'football' is 'f'.
The initial letter of 'left' is 'l'.
'f'+'ow'+'l'='FOWL'
Can you help me to learn more?
(Other definitions for fowl that I've seen before include "Bird to be eaten or hunted as game" , "eg hen" , "Domestic birds" , "Bird, maybe domestic" , "Poultry bird" .)