jargon.artrocity.com
New Hacker's Dictionary the Jargon File v 4.4.6
1. To introduce a typo while editing in such a way that the resulting manglification of a configuration file does something useless, damaging, or wildly unexpected. “NSI fat-fingered their DNS zone file and took half the net down again.”
2. More generally, any typo that produces dramatically bad results.