Deter is a verb that means to discourage or prevent from taking action. There are several synonyms for this word, including dissuade, discourage, hinder, inhibit, and restrain. Dissuade is used when someone is trying to talk another person out of doing something. Discourage is used when someone is trying to dampen the enthusiasm or confidence of another. Hinder is used when someone or something is making it difficult for progress to be made. Inhibit is used when something is suppressing or preventing a natural tendency. Restrain is used when someone is trying to hold back or prevent someone from doing something. These synonyms can be used interchangeably to express the idea of stopping or preventing someone from taking action.