final nail in the coffin

another nail in someone's coffin

An event that increases the likelihood of or causes further failure.

China's final warning

A warning that carries no real consequences; an empty threat.

final cut

In the movie industry, the final released version of a film.

final say

The right to make a final decision.

hit the nail on the head

To identify something exactly; to arrive at exactly the right answer.

last nail in the coffin

Alternative form of final nail in the coffin.

nail down

to make something (e.g. a decision or plan) firm or certain

nail the hammer on the head

Nonstandard form of hit the nail on the head.