Haijin is a direct romanization of the Japanese word which originally meant "cripple", but was later adopted by the online gaming subculture, to describe gamers who spent so long playing that they were assumed to never venture out of the house. In other words, incapacitated, like a cripple.
Rick's such a haijin he got to level 70 in just two weeks.
by JonnyRam August 11, 2004