Fear, uncertainty and doubt (FUD) is a tactic used by some people to try to keep others from making decisions that they don't want them to make. It works by making people afraid to decide, uncertain of what the right decision is, or doubtful of the truth of the information they have been told. Imagine someone trying to convince you not to buy a certain toy because it hasn't been tested and might be dangerous. That's an example of FUD - they're trying to make you afraid of buying the toy, uncertain about how safe it is, and doubtful about the information you have about it.