speed up . speed up {v.} To go faster than before; also, to make go faster. The car speeded up when it reached the country. Push in the throttle to speed up the engine. Compare: PICK UP (12). Contrast: SLOW DOWN. Categories: add yours {v.} Source: A Dictionary of American Idioms by A. Makkai, M.T. Boatner, J.E. Gates © 2024 » In RussianTo section: S Subscribe to: American IdiomsIdioms feedEnglish languageHome page and general feed Comment on this entry