There are several synonyms for the term "unwise saying." One synonym is the phrase "foot in mouth," which describes saying something foolish or inappropriate. Another synonym is "faux pas," which refers to a social mistake or blunder. "Blunder" itself is a synonym for an unwise saying, and it describes a careless or thoughtless mistake. "Gaffe" is another synonym that is often used to describe a verbal mistake or blunder that occurs in a social or professional setting. "Folly" is another term that can be used to describe an unwise saying, as it implies that the speaker has made a foolish or irrational decision.