Nearly, but not quite, the opposite of innovation. Denovation is ostensibly the abandonment of an idea or technology, a stepping back from something that had formerly been seen as a step forward.
Sometimes, denovation results from superstition or other foolishness; this happens most often in post-apocalyptic science-fiction stories, but there are plenty of historical cases to do with medicine and hygiene. Sometimes, there's a political objective, as with the Taliban's attack on modern technology to assure their cultural primacy. Sometimes there are more mundane reasons for denovation, as with the Bennett buggy -- economic conditions, for example, can make a technology or idea unfeasible.
Sometimes, however, a denovation can actually be a step forward. One canonical example is recent renewed interest in push-powered lawnmowers: they're quieter, cheaper to run, and better for the environment than the gas-powered or electrical ones, and with modern materials, they work at least as well for actually getting most lawns mowed.
The lawnmower example illustrates the principle working well, with old and new technology combining to make something better. But it definitely required abandoning the idea that motors make mowing the lawn easier.