Now proud; then undone before the fall (8)

I believe the answer is:

downpour

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'the fall' is the definition.
(I have seen 'Big fall' mean 'downpour' so perhaps 'fall' could also mean 'downpour')

'now proud then undone before' is the wordplay.
'now proud' anagrams to 'DOWNPOUR'.
Though, I am not clear how the anagram is indicated.

Can you help me to learn more?

(Other definitions for downpour that I've seen before include "falling water" , "Cloudburst" , "Now proud (anag)" , "Heavy continuous rainfall" , "Torrent" .)

I've seen this clue in The Globe and Mail.

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