Every one's faults are not written on their foreheads.

A person's failings are not immediately visible. Outward appearance, reputation, or a single encounter cannot reveal everything that person has done wrong or struggles with.

The saying counsels humility in judging others. It can also remind someone that private shortcomings may remain hidden, so apparent innocence or respectability should not be treated as proof of blamelessness.

Use it when cautioning against quick moral judgments based on appearances or limited knowledge. It suits a reflective discussion of concealed weaknesses and the need to allow for uncertainty about another person's character.