breakneck

moving, proceeding, or acting with great speed the breakneck production of naval vessels during World War II Synonyms blistering, fast, breathless, brisk, dizzy, fleet, fleet-footed, flying, galloping, hasty, hot, lightning, nippy, quick, rapid, rapid-fire, rattling, snappy, speedy, splitting, swift, whirlwind, zippyRelated Words expeditious, prompt, ready; accelerated, hastened, hurried, quickened, rushed; breathtaking; energetic, strenuous, strong, vigorous; high-speed; rush; ultrafast, ultrarapidNear Antonyms crawling, dallying, dawdling, dillydallying, dragging, laggard, languid, lingering, plodding, poking, poky (or pokey), slowish, sluggish, unhurried; deliberate, leisurely, measured; dilatory, late, tardy; ultraslowAntonyms slow