A Computer Scientist - one who is studying for a Bachelor of Arts in Computer Science.
This Art / Science dichotomy is probably one reason so many of them are insane. Although they themselves disagree, claiming to have been insane to start with - and point to their presence in Cambridge as proof.
CompScis have many strange traditions and religions which are almost opaque to the outside observer. Their worship of Thor, their protests at the Phoenix room, the capture of a unicorn on the third floor... and many many others. Alas, times are changing, and Thor is no more.
They also have long-standing rivalries - mostly with the other XScis: NatScis and MathMos, with whom they compete for space.
In this, unfortunately modern, era, they now have the ComputerLab buildings to inhabit.
CompScis are among the less dangerous nocturnal inhabitants of Cambridge. Contrast with the AssassinsGuild, however beware, as some of the CompScis are also members of the Guild...
People might like to take a look at [this][and this] MacHall? strip for further information....
The term appears to have expanded in popular usage to include practically the entirety of Spod?. --Vitenka