What this suffix does
-faced forms compound adjectives that describe the face as a surface of moral and emotional expression. Two-faced, barefaced, bold-faced, hard-faced, straight-faced — each compound uses the face as a site of moral revelation. The face in these compounds is not a purely physical feature but a moral signal: it shows what a person is willing to display and what they are able to conceal. "Barefaced" and "bold-faced" exploit the vulnerability of an uncovered face; "two-faced" exploits the impossibility of having two faces. These are among the most vivid character judgments in English.