To 'boire la tasse' translates as to go under, sink, fail or be defeated by something.
Word-for-word, boire la tasse means to 'drink the cupful'.
This expression first appeared in the Dictionary of the Académie française in 1798, with a definition explaining “one says ‘to drink from the big cup’ to mean drowning in the sea’.
In fact, when the word tasse – cup – arrived in France from Persia in the 14th century it was originally tasse grande referring to a vase-sized vessel, much larger than the mugs for hot drinks we think of today.
As such, drinking such a large cupful of water was seen as a sure way to sink to the bottom.
Today the expression boire la tasse can mean simply swallowing a lot of water accidentally while swimming.
But, it can also mean to fail, lose badly, lose a lot of money or go under.