FDR's agreement all needs to be sorted out before end of battle (4-5)
I believe the answer is:
lend-lease
'fdr's agreement' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'all needs to be sorted out before end of battle' is the wordplay.
'to be sorted out' is an anagram indicator.
'before' says to put letters next to each other.
'end of' says to take the final letters.
The last letter of 'battle' is 'e'.
'all'+'needs'='allneeds'
'allneeds' anagrammed gives 'lendleas'.
'lendleas'+'e'='LEND-LEASE'
Can you help me to learn more?
(Other definitions for lend-lease that I've seen before include "US provision of military equipment to the UK and its allies in World War II" , "WWII arrangement; ladle seen (anag.)" .)