A person who intentionally takes the joy of another person and brutally murders it with no remorse.
Girl: Yesh, finally Full Metal Alchemist. Oh how I've longed for you. *kisses television*
Mom: No FULL METAL ALCHEMIST. Japan is evil.
Girl: Geez Mom, you're such a kill-joy!
Girl: Yesh, No school because of snow!
Weather Man: Looks like school is back in session due to the sudden elevation of tempurature.
Girl: Geez Mr. Meteorologist Man Guy, you're such a kill-joy.