Fall flat on your face Definition 1 of 3Pro Tip 1/3Colloquial Metaphor Used informally to describe a big failure, not a literal fall. He tried to joke during his speech, but he fell flat on his face. Pro Tip 2/3Humorous Imagery Sometimes used to add humor when talking about failures. She fell flat on her face with that karaoke performance. Pro Tip 3/3Public Events Often used when a failure occurs in front of others, adding to embarrassment. At the debate, his arguments fell flat on their face.