From Longman Dictionary of Contemporary Englishdeath knellˈdeath knell noun [singular] WARNa sign that something will soon fail or stop existing → death blow(sound/strike/toll) the death knell for/of something The loss of Georgia would sound the death knell of Republican hopes.
Examples from the Corpus
death knell• The word repeated itself over and over in her head like a death knell.• Do we now hear yet another death knell for readability studies?• Was it the death knell of the nuclear industry or merely curfew time?• This would, in effect, finally sound the death knell for the Convention.• The death knell for a revised Thanksgiving came when retailers began admitting their revenues had not improved after all.(sound/strike/toll) the death knell for/of something• The death knell for a revised Thanksgiving came when retailers began admitting their revenues had not improved after all.• Croson to be the death knell for minority contracting laws, many big city officials refused to give up.• Nor is Mr Gore's loss going to be the death knell for the environment that Preston claims.• Was it the death knell of the nuclear industry or merely curfew time?• This would, in effect, finally sound the death knell for the Convention.• Energy analyst Walt Patterson believes this would sound the death knell for research. 