IPA: //ˈbɛərˌfeɪst//
KK: /ˈbɛrˌfeɪst/
Not covered or concealed; showing boldness or shamelessness without any disguise.
He made a barefaced attempt to lie to his boss without any shame.
Barefaced is formed from "bare" (from Old English "bær", meaning uncovered or exposed) and "faced" (from the root "face", which comes from Latin "facies", meaning appearance or surface). The word describes someone who is openly shameless or without disguise, as if their face is bare or uncovered.
Think of someone whose face is 'uncovered' ('bare') and showing no shame — that's what 'barefaced' means.