Crossword Genius

Endlessly regretting penury (4)

Ross

I believe the answer is:

ruin

I'm a little stuck... Click here to teach me about this clue!

Here is my best explanation:

'penury' is the definition.
The answer and definition can be both states of affairs as well as being singular nouns.
Perhaps you can see an association between them that I can't see?

'endlessly regretting' is the wordplay.
'endlessly' means to remove the last letter.
'regretting' becomes 'ruing' ('rue' can be a synonym of 'regret').
'ruing' with its last letter taken off is 'RUIN'.

Can you help me to learn more?