“Fair of face” means beautiful or pleasant-looking , especially with a lovely or attractive face. It’s an older, poetic phrase, so you’ll most often see it in literature or nursery rhymes rather than everyday speech.

In context

In the line “Monday’s child is fair of face,” the phrase is part of an old fortune-telling rhyme and suggests a child born on Monday is attractive or blessed with a pleasing appearance.

It does not mean “fair” in the sense of just or equitable.

Simple paraphrase

  • “Fair of face” = “good-looking.”
  • “Fair in the face” = “having a beautiful face.”
  • In old-fashioned usage, “fair” could also mean light-complexioned or lovely.

Example

  • “She was fair of face and gracious in manner.”
    This means she was attractive and carried herself well.

TL;DR: it’s an old-fashioned way to say someone is beautiful, especially in the face.