bold-faced lie
A blatantly obvious and/or impudent untruth, one in which the liar does not attempt to disguise their mendacity. Sir, I have never done these things of which you accuse me; they are bold-faced lies, and nothing more.
bold-faced liar
One who tells blatantly obvious and/or impudent untruths easily and with little or no attempt to disguise the lie. Everyone knows he is just a bold-faced liar. It's a wonder anyone believes a thing he says anymore.