What is a large draught of drink called?

There are a few ways to describe a large draught of drink, depending on the context and the desired level of formality:

Formal:

* A copious draught: This emphasizes the large quantity.

* A generous libation: This implies a large amount, often served ceremonially.

* A substantial drink: This emphasizes the size of the drink.

Informal:

* A big gulp: This is a casual way to describe a large, quick drink.

* A chug: This is a slang term for drinking quickly and in large amounts.

* A swig: This is a more general term for a large drink, but can be used for any size.

* A tanker: This is a slang term for a very large drink, often used in a humorous context.

The best term to use depends on the situation and the speaker's tone.