mix up . mix up {v.} To confuse; make a mistake about. Jimmy doesn't know colors yet; he mixes up purple with blue. Even the twins' mother mixes them up. Compare: MIXED UP. Categories: add yours {v.} Source: A Dictionary of American Idioms by A. Makkai, M.T. Boatner, J.E. Gates © 2024 To section: M Subscribe to: American IdiomsIdioms feedEnglish languageHome page and general feed Leave my opinion