Frankenbiting

Though it’s tempting to keep rehashing the widespread academic and other evidence of worker exploitation and stolen wages (US$40 million a year by New York based, non-scripted TV companies alone in 2013, according to the Writer’s^([sic]) Guild of America), pitifully cheap production values, links to mass plastic surgery, eating disorders and generally diminishing morality in audiences, “frankenbiting” (where dialogue is deceptively edited to create better stories), metadata surveillance, the impoverishment of public discourses and the fact the that the whole thing is predicated on being real when it is extraordinarily fake – there is another aspect to reality TV that makes it even worse.

Source: wiktionary

If you see someone talking before the camera cuts to a shot of something else while the voice continues, that's likely frankenbiting.

Source: wiktionary

Sometimes, Frankenbiting isn't even bothered with. There have been reports that Paris Hilton was fed specific lines to speak on her show The Simple Life.

Source: wiktionary