Prospect following land clearance (4,3)

I believe the answer is:

open sea

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I'm afraid I can't even guess how this answer relates to the clue.

(Other definitions for open sea that I've seen before include "Clear ocean" , "Unenclosed stretch of water" , "body of water away from land" , "Waves at large" , "Unenclosed ocean" .)

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

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