Potential Irish windfall for darling Bill
I believe the answer is:
sweet william
'potential irish windfall' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'darling bill' is the wordplay.
'darling' becomes 'sweet' (I've seen this before).
'bill' becomes 'william' (I've seen this before**).
'sweet'+'william'='SWEET-WILLIAM'
'for' is the link.
Can you help me to learn more?
(Other definitions for sweet william that I've seen before include "Flowering plant - Prince at sixteen?" , "Eurasian plant with fragrant flowers" , "description Violet Elizabeth wouldn't have recognised?" , "Plant with clusters of coloured flowers - WWI allies met (anag)" , "Flower (nice boy!)" .)