lock up . lock up {v. phr.}, {slang} To be assured of success. How did your math test go? — I locked it up, I think. Categories: add yours success {slang} {v. phr.} Source: A Dictionary of American Idioms by A. Makkai, M.T. Boatner, J.E. Gates © 2025 To section: L Subscribe to: American IdiomsIdioms feedEnglish languageHome page and general feed Leave my opinion