Normally, "bootleg" refers to goods illegally sold and distributed, without proper taxation, and at a loss to the original manufacturer of the goods. This can apply to anything, from booze to cigarettes to designer jeans, etc, as long as it is sold and distributed by other than legal means. Today the term is primarily used to describe stolen audio/video recordings that are illegally sold and distributed on the Internet.

A pirated copy of something.

Not always guaranteed to be reliable because, of course, it isn't the original.

The opposite of Legit

Bootleg recording

A bootleg recording is a audio or video recording of a performance that was not officially released by the artist or under other legal authority. A great many such recordings are simply copied and traded among fans of the artist without financial exchange, but some bootleggers are able to sell these rarities for profit, sometimes by adding professional-quality sound engineering and packaging to the raw material.

Although the real word means pirated music/software and illegal alcohol, the slang term means wrong, broken, fake, or bullshit

n. an unofficial recording of a concert

This term originated with smugglers and thieves who would hide things in the leg of their boots. It evolved to mean a pirated version of something. Some liberal bands such as the Grateful Dead, and more recently Phish and Pearl Jam allow fans to record their concerts, and distibute these recordings freely as long as they are not sold. Fans refer to such recordings as "bootlegs", even though they are legal.

A describing word for something that sux or is bad.
Also can be used as "Boot-legger" to describe a slacker.