the final nail in the coffin

US /ðə ˈfaɪnl neɪl ɪn ðə ˈkɔfɪn/
UK /ðə ˈfaɪnl neɪl ɪn ðə ˈkɔfɪn/
"the final nail in the coffin" picture
1.

o golpe final, o último prego no caixão

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.
O último escândalo da empresa foi o golpe final para sua reputação.
His decision to quit was the final nail in the coffin for the struggling project.
Sua decisão de sair foi o golpe final para o projeto em dificuldades.