Catches on as one falls (7)

I believe the answer is:

tumbles

I believe this clue is a double definition.

'catches on' is the first definition.
('tumble' can be a synonym of 'catch on')

'one falls' is the second definition.
('tumble' can be a synonym of 'fall')

'as' is the link.

(Another definition for tumbles that I've seen is " Falls headlong, like Jill after Jack".)

I've seen this clue in the Evening Standard.

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