One with particular interest in offering ready supply (11)
I believe the answer is:
Here is my best explanation:
'one with particular interest in' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'ready supply' is the wordplay.
'ready' becomes 'money' (I've seen this before).
'supply' becomes 'lender' (I can't explain this - if you can you should give a lot more credence to this answer).
'offering' is the link.
(Other definitions for moneylender that I've seen before include "One advancing at interest", "Loan provider" and "Usurer".)