Make slow progress on land; fast in water (5)

I believe the answer is:

crawl

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'make slow progress' is the definition.
(I've seen this before)

I can't explain the rest of the clue.

(Other definitions for crawl that I've seen before include "Proceed on hands and knees" , "Suck up to" , "Go on all fours" , "This can take you quickly through water" , "Move as snakes do, or on hands and knees" .)

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

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