A word often used by anime characters. (Usually the anti-social/ broody/
cold/ tortured types. Ex. Hiei from Yu Yu Hakusho.)
It is a universal bitchy answer to anything anyone says. The character says it when they could care less, or when they are being a jerk. Which is probably all the
time. (Can even be used as a greeting, it's
pretty versatile. Like grunting to communicate.)