Apparently its "a person who spoils other people's fun or enjoyment" hummmm.... sounds like a lot of lazy and selfish people to me.
You know how it goes, usually starts off with something like this.
question: "Hey mom needs a lift to the market on saturday"
answer: "ohhh saturday I'm tied up with work in the morning"
reply: "ok no problem you can take her in the afternoon that will work too"
answer: "well you know by then i'll be tired from work and need some rest"