coffin nail—
1. smth. (in a sequence of events) that tends to do serious harm:
- Every time they buy products made in other countries they are driving another coffin nail into America’s economy.
2. (sl.) a cigarette:
- Our joking doesn’t seem very funny any more, because for many thousands, cigarettes really do become coffin nails.
nail in the coffin— = coffin nail 1:
- The vote is another nail in the coffin of the one-party system which the country has now largely renounced.