Green leader prepared to admit source of money (7)
I believe the answer is:
emerald
'green' is the definition.
(I've seen this before)
'leader prepared to admit source of money' is the wordplay.
'prepared' is an anagram indicator.
'to admit' indicates putting letters inside.
'source of' suggests taking the first letters.
The first letter of 'money' is 'm'.
'leader' anagrammed gives 'eerald'.
'eerald' enclosing 'm' is 'EMERALD'.
(Other definitions for emerald that I've seen before include "and 1 Across: Ireland" , "Green like this isle" , "Ireland is often called The .......Isle" , "Precious green stone" , "Green - jewel" .)