To premeditate means to plan something carefully before doing it, especially something wrong or harmful.

The word appears most often in serious contexts. In criminal law, a premeditated crime is one that was planned ahead of time, which makes it more serious than a crime committed in the heat of the moment.

The key element is intention and planning. If you accidentally knock over your brother's science project, that's not premeditated. But if you spend days figuring out exactly when and how to do it without getting caught, that's premeditation. The planning shows the action wasn't accidental or impulsive. It was deliberately thought through, which is why premeditated acts often carry greater consequences than spontaneous ones.