vocab for the week 36

What is the meaning and origin of the expression ‘kiss of death’?

In the old movies dealing with the Mafia, whenever the Don kissed someone squarely on the mouth, it meant the person was going to be ‘bumped off’ soon. It was the kiss of death. The idiom ‘kiss of death’ refers to an action which results in the ruin or failure of something. It is the instrument of a person’s downfall.
Throwing up on the stage was the kiss of death for Rahul’s acting career.
The origin of the idiom, however, has nothing to do with the Mafia. Judas helped identify Jesus to the Roman authorities by kissing him. The idiom ‘kiss of death’ refers to the betrayal of Jesus by Judas in the Garden of Gethsemane. The earlier expression, I understand, was ‘Judas kiss’.