coup de grâce or coup de grace 
/ˌku:dəˈgrɑ:s/ noun
plural coups de grâce or coups de grace /ˌku:dəˈgrɑ:s/ noun /ˌku:dəˈgrɑ:s/ [count] formal 1 : an action or event that finally ends or destroys something that has been getting weaker or worse
▪ The legislature's decision to cut funding has administered the coup de grâce to the governor's proposal. 2 : a hit or shot that kills a person or animal that is suffering
▪ The legislature's decision to cut funding has administered the coup de grâce to the governor's proposal.
