Complain win against one side's overshadowed (5)
I believe the answer is:
bleat
'complain' is the definition.
(I know that bleat is a more specific form of complain)
'win against one side's overshadowed' is the wordplay.
I cannot really understand how this works, but
'one' could be 'a' (a thing is one thing) and 'a' is found within the answer.
'side' could be 'l' (abbreviation for left) and 'l' is present in the answer.
The remaining letters 'bet' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for bleat that I've seen before include "Table (anag.)" , "Make complaint" , "kid makes such a noise" , "Cry of animal" , "Whine" .)