Pasted from the thread on mediaeval swearing:

"So, a quick poke around the Oxford English Dictionary reveals that "shit" comes from the olde English for diarrhoea, scitte, which is itself Germanic in origin, from scheissen, possibly via the Danish shitjen. So it's one that's been with us for some time. Shite too goes back along way, and was even used to describe a whole range of birds in the heron family during the late 18th century: shitepokes were allegedly so called for their habit of crapping themselves when disturbed. Good to see twitchers had a sense of humour back then. "