Fight and fight again, nothing less (5)
I believe the answer is:
foray
'less' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'fight and fight again nothing' is the wordplay.
I cannot really see how this works, but
'nothing' could be 'o' (looks like zero - 0) and 'o' is located in the answer.
'fight' could be 'fray' (fray is a kind of fight) and 'fray' is found within the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for foray that I've seen before include "Depredation" , "Raid into enemy territory" , "Raid or incursion" , "Sortie" , "Brief incursion" .)