COMMON If an event is another nail in the coffin of something or someone, it is the latest in a series of events which are seriously harming that thing or person. The vote is another nail in the coffin of the one-party system which the country has now largely rejected. The President took the blame for the crisis and it became another nail in the coffin of his leadership. Note: If you say that an event is the last nail or the final nail in the coffin of something or someone, you mean that it finally destroys something or causes someone to fail. A rent increase could be the final nail in the coffin for a small business like this. The marriage was already in trouble and his affair proved to be the last nail in the coffin.