old as the hills . old as the hills {adj. phr.} Very old; ancient. "Why didn't you laugh?" she asked. "Because that joke is as old as the hills," he answered. Categories: add yours {adj. phr.} Source: A Dictionary of American Idioms by A. Makkai, M.T. Boatner, J.E. Gates © 2024 To section: O Subscribe to: American IdiomsIdioms feedEnglish languageHome page and general feed Post my comment