to challenge someone to do something. Sally dared Jane to race her to the corner.You wouldn't do that, would you? I dare you.
You wouldn't dare (to do something)!
an exclamation that shows disbelief about something that the speaker has stated an intention of doing. Bill: I'm going to leave school. Tom: You wouldn't dare leave! Bill: Be quiet or I'll slap you. Jane: You wouldn't dare to slap me!
don't you dare
(spoken)
I will be very angry at you if you do "I'm going to tell Billy what you said about him." "Don't you dare! "
1. I venture to assert or affirm, as in I dare say my point of view will be heard. [c. 1300]
2. Also, I daresay. I presume or assume to be likely, as in I daresay you'll be invited. This usage is more common in Britain than in America. [Mid-1700s]