1 to stop or destroy a relationship, activity, or experience: --
2 to cause someone a lot of effort or difficulty: --
4 If you say that someone will kill you, you mean that they will be very angry with you: --
5 to make someone laugh a lot: --
It is hoped that the kidnappers will not carry out their threat to kill the hostages.
The humane way of dealing with a suffering animal is to kill it quickly.