You use barefaced about a lie, excuse, or unkind act that is out in the open — anyone can see it is false or rude — and the person does not even try to hide it or look sorry. The set phrase is a barefaced lie: they know you can tell it is not true, and they say it anyway. It is a judging word, rather strong, a little old-fashioned, more at home in complaints and news than in friendly talk. You would not call a quiet, clever lie barefaced; the whole point is that there is no mask on it. Though actually, this is not the everyday 'bare' of bare skin. People picture a face with nothing covering it, so the wrongdoing is not wearing a disguise. Scholars also wonder whether it grew out of an older word like barefast, in the family of shamefast (held back by shame). If that is right, barefaced is almost the opposite: the shame has been stripped off. Either way, in today's English it means shameless and obvious, not 'with no make-up'.

厚顏無恥的（常配 lie：厚顏無恥的謊言）