The other day, I was trying to convey the meaning of the
Last nail in the coffin.
The literal translation
Dernier clou dans le cercueil.
seems to be unknown to natifs. (Some students didn't remember/know the word cercueil but that's another story:-)!).
Trying to find other possible translations we encounter "coup fatal" et "sonner le glas". The former was understood, the latter considered a bit archaic.
What are some common colloquial ways to express the meaning of the original English sentence?
As an example of usage:
An employee keeps arriving late for work. His boss gives him a first warning. The employee is late again. His boss gives him a second warning. The employee is late again. His boss gives him a third warning, and says, “If you’re late again, you’re fired.” The employee shows up the next day 2 hours late. The boss says, “Your late arrival today is the final nail in the coffin. You’re fired.