let slip let slip {v. phr.} To unintentionally reveal. Ellen let it slip that she had been a witness to the accident. Categories: add yours {v. phr.} Source: A Dictionary of American Idioms by A. Makkai, M.T. Boatner, J.E. Gates © 2024 To section: L Subscribe to: American IdiomsIdioms feedEnglish languageHome page and general feed Post my comment