AVADA KEDAVRA
One of the three unforgivable curses (punished by life imprisonment in Azkaban). When performed a green light is emitted from the wand. The subject of this curse is killed instantly. There is no counter curse.
Latin: avaiter= greedy, covetous
avidus= avaricious
French: avare= avaricious
Arabic: avada kedavra= I destroy
Book: Goblet of Fire