believe in the tooth fairy

1. To believe in a mythical fairy who exchanges money for children's baby teeth that have fallen out and been placed beneath their pillow at night. My daughter still believes in the tooth fairy, and it's pretty darn cute to see how excited she gets when she loses a tooth. When you've got five little ones who all believe in the tooth fairy, it gets kind of expensive! A: "Hey Mom, any chance I can get some money in exchange for the teeth the dentist pulled?" B: "Come on, I know you don't believe in the tooth fairy anymore!"

2. By extension, to believe in something that is utterly fanciful, unrealistic, or absurd. To believe that the leaders of this company are interested in anything but their own profits is to believe in the tooth fairy! If you think that the legislation is going to fix the issues with healthcare in this country, then you might as well believe in the tooth fairy! You really think we're getting bonuses this year? And do you believe in the tooth fairy too?