the final nail in the coffin
US /ðə ˈfaɪnl neɪl ɪn ðə ˈkɔfɪn/
UK /ðə ˈfaɪnl neɪl ɪn ðə ˈkɔfɪn/
1.
an event that causes the failure of something that had already been weakening
:
•
The company's latest scandal was the final nail in the coffin for its reputation.
•
His decision to quit was the final nail in the coffin for the struggling project.