"Coup de grâce" is a phrase borrowed from French, meaning "blow of mercy". It is used to describe the final act needed to finish off a wounded or defeated opponent, and is often associated with death or destruction. However, there are several synonyms that can be used in its place to convey the same concept. "Final blow", "death knell", "kill shot", "finishing move", "last rites", and "clincher" are all synonyms that can be used to describe the act of delivering the final blow to an already defeated opponent. Each of these words brings its own nuances and connotations to the table, but they all serve to describe the finality of a decisive action.