Fall in the sea (3)

I believe the answer is:

ebb

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'fall' is the definition.
(I've seen this before)

I don't understand the rest of the clue.

(Other definitions for ebb that I've seen before include "Tidal outflow" , "Receding movement, as of a tide" , "(Sea) recede" , "Withdraw heartless" , "Type of tide" .)

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

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