From Jargon File (4.3.1, 29 Jun 2001) :
suit n. 1. Ugly and uncomfortable `business clothing' often worn by
non-hackers. Invariably worn with a `tie', a strangulation device that
partially cuts off the blood supply to the brain. It is thought that
this explains much about the behavior of suit-wearers. Compare droid.
2. A person who habitually wears suits, as distinct from a techie or
hacker. See pointy-haired, burble, management, Stupids, SNAFU
principle, PHB, and brain-damaged.