Financial arrangement protecting Charlie's not so good in retirement (6)
I believe the answer is:
escrow
'not so good in retirement' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'financial arrangement protecting charlie's' is the wordplay.
'financial' becomes 'es' (I can't explain this - if you can you should believe this answer much more).
'arrangement' becomes 'row' (row is a kind of arrangement).
'protecting' indicates putting letters inside.
'charlie' becomes 'c' (phonetic alphabet: alpha, bravo, charlie etc.).
'es'+'row'='esrow'
'esrow' enclosing 'c' is 'ESCROW'.
Can you help me to learn more?
(Other definitions for escrow that I've seen before include "It's held in trust or as a security" , "Something held until a condition is fulfilled" , "conditional execution of deed" , "Legal deed to take effect when a condition is fulfilled" , "fund held in trust?" .)