The drink last in line nobody is able to swallow (5)

I believe the answer is:

ocean

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'the drink' is the definition.
('the drink' is an informal term for the sea)

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for ocean that I've seen before include "Huge sea" , "It's pretty wet!" , "Large area of water" , "Immense expanse or quantity" , "Very large area of sea" .)

I've seen this clue in The Independent.

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