dare

If you dare to do something, you have the courage to do it, even if you are afraid.

Example: The President dared to make an unpopular decision.

If you dare someone to do something, you challenge them to do something that is a risk, or even dangerous.

Example: I dare you to climb that tree.

If you dare not do something, you are afraid to do it.

Example: I daren't tell my parents what happened. They'll be very cross.

You say How dare someone do something? to show that you are angry about something that someone has done.

Example: How dare you come in here without knocking?

A dare is a challenge to somebody.

Example: He never says "No" to a dare.