You know those intrusive thoughts you sometimes get when someone has done something to you, and you just want to get them back in a way that will really ruin their day? I mean, hopefully we don't actually follow through with the plan. But when someone deliberately works to damage or undermine something, there's a word for it: sabotage.  

You can sabotage a machine, a plan, a business—or even your own chances of success.  Nowadays we think of it as something that is done on purpose, but the word didn’t start off that way.  

Sabotage comes from French, and it's connected to something much less threatening: a wooden shoe. A sabot was a type of wooden shoe worn in parts of Europe. The French verb saboter originally had meanings connected to making a clattering noise with those wooden shoes. Eventually, it also came to mean doing something clumsily—or botching it. By the early 1900s, sabotage had taken on its modern meaning of deliberately damaging or obstructing something.

There are rumors that the word is related to French factory workers who threw their wooden shoes into machines to break them. Great story—but there's no good evidence that actually happened.

So the next time somebody deliberately messes up a plan, damages equipment, or works against their own success, you can call it sabotage.