تعریف و معنای "[fall] flat on {one's} face"

What is the origin of the idiom "fall flat on one's face" and when to use it?

The origin of the idiom "fall flat on one's face" is unclear, but it may have originated from the literal act of falling forward and landing on one's face, which is a highly visible and embarrassing physical mishap. Over time, the phrase has come to be used more generally to describe any situation where someone fails in a highly noticeable or embarrassing way, often resulting in public humiliation or a loss of reputation.