Wi-fi internet connection from an unauthorized source, and accessing it when you're supposed to be at work.
Since my company decided to monitor our internet usage, I've been using my iPhone to access a sly-fi network from another company nearby to check my facebook and watch you-tube videos.
by cdafox July 13, 2011
1 more definition
Science fiction that also is humorous, like the "Hitchhiker's Guide to the Galaxy" and the BBC's "Red Dwarf."
Did you catch that sly-fi marathon on PBS the other night?
by LRK June 07, 2006