Being on the drink might cause it? (3,2,3)

I believe the answer is:

mal de mer

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'being' is the definition.
The answer and definition can be both states of affairs as well as being singular nouns.
Maybe they are linked in a way I don't understand?

I can't explain the rest of the clue.

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(Other definitions for mal de mer that I've seen before include "Seasickness (French)" , "type of sickness" , "problem on board" .)

I've seen this clue in The Guardian.

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