Antonyms of swift:
slow, clumsy, dull, heavy, inactive, inert, sluggish, unready, dilatory, crawling, dallying, dawdling, dillydallying, dragging, laggard, languid, lingering, plodding, poking, poky, slowish, unhurried, deliberate, leisurely, measured, late, tardy, ultraslow.
Examples of usage:
  1. " Come," he said with swift decision.
    "The Heart of Unaga", Ridgwell Cullum.
  2. Even the minutes of suspense seemed good because they had brought at last this swift rush of happiness.
    "Virginia", Ellen Glasgow.
  3. She fell to her knees with swift grace.
    "Whispering Wires", Henry Leverage.