barefaced lie
A blatantly obvious and/or impudent untruth, one in which the liar does not attempt to disguise their mendacity. My opponent's assertion that I intend to raise the tax rates is baseless; it is nothing but a barefaced lie.
barefaced lie
A shameless falsehood. For example, Bill could tell a barefaced lie with a straight face. The adjective barefaced means "beardless," and one theory is that in the 1500s this condition was considered brazen in all but the youngest males. By the late 1600s barefaced also meant "brazen" or "bold," the meaning alluded to in this phrase.