tack on . tack on {v. phr.} To append; add. We were about to sign the contract when we discovered that the lawyer had tacked on a codicil that was not acceptable to us. Categories: add yours {v. phr.} Source: A Dictionary of American Idioms by A. Makkai, M.T. Boatner, J.E. Gates © 2024 » In RussianTo section: T Subscribe to: American IdiomsIdioms feedEnglish languageHome page and general feed Add my comment