If you do something bald-faced, you do not even try to hide that you know it is wrong. The phrase you will hear most is a bald-faced lie: a lie told with a straight face, as if it were obvious and you do not care that people can see through it. The bald here is an older meaning, “bare, with nothing covering it” — like a hill with no trees — not mainly “with no hair.” Some people write bold-faced lie, as if the liar were being bold, and you will see that in print, but the older form is bald-faced; another old twin is barefaced. All three turn up in real life, which is messy.