A person who puts an end to a funny joke, or line of jokes.
When someone tries to be funny but instead stops everyone else from laughing.
Elmo(Hypebeast) from excentrixgamingis a joke killer.
We are on Ventrilo telling jokes and laughing at stupid shit and elmo will come out of nowhere and kill the joke.
Elmo gets paid $2.15 an hour to kill jokes.
Albeezy "Id have to be hella high to laugh at one of Elmo's jokes, stupid nigga kills everything."