If someone lies through their teeth, they tell obvious lies and do not seem to be embarrassed about this. We ought to be mad that public officials lie through their teeth. `We were on vacation in Barbados a few years ago and we met Brad Pitt in a bar,' says Phil, lying through his teeth. Note: In British English, you can also say that someone lies in their teeth. I should have known he was lying in his teeth when he said he would pay more than we were owed.