If you call someone a fool, you are indicating that you think they are not at all sensible and show a lack of good judgment.

If you fool around, you behave in a silly, dangerous, or irresponsible way.

If you make a fool of someone, you make them seem silly by telling people about something stupid that they have done, or by tricking them.

If you make a fool of yourself, you behave in a way that makes other people think that you are silly or lacking in good judgment.

If you play the fool or act the fool, you behave in a playful, childish, and foolish way, usually in order to make other people laugh.

If someone fools you, they deceive or trick you.

If you say that a person is fooling with something or someone, you mean that the way they are behaving is likely to cause problems.