Another/the final nail in the coffin noun phrase
A coffin used to be made of wood and was sealed up with nails before burial, so the final nail is the last one used to completely close the coffin.
Don't be late again or it'll be the final nail in the coffin.
Not being able to meet that important requirement put another nail in the coffin of their careers.
To quit; to give up, stop doing something because you know that you cannot succeed; admit defeat
a joke, idea, or suggestion falls flat, meaning that it does not achieve the intended effect.
A child with great talent and intelligence will lose those qualities over time.
This phrase first appeared in the eighth open letter that the English political writer Thomas Paine (1737-1809) addressed to the citizens of the United States, denouncing the Federalist party: Thomas Paine - an English political activist
In his late unprincipled speech in the legislature of that state, he has driven another nail in the coffin of the federal faction […].
To do something in an unusual way
I guess I like to run against the grain in everything I do.