How to say "swiftly" in Japanese

• 急にきゅうにJLPT N3approx.Common
  adverbCovers 'swiftly' when the point is abruptness: an action or change begins suddenly, without warning. It stresses sudden onset rather than smooth speed, so it is seldom the word for plain fast movement.
  気苦労きぐろうで彼かれは急きゅうにふけた。↗

  Care aged him quickly.
• パッとCommon
  adverbMatches 'swiftly' as 'in a flash': a short, snappy action completed in an instant, such as turning around or grabbing something. As a mimetic word it adds a vivid, light touch to the description.
  レース中ちゅうにその車くるまはぱっと燃え上もえあがった。↗

  The car burned up in the race.
• 早くはやくCommon
  adverbThe general-purpose choice for 'swiftly' as plain speed: doing or moving fast, with no special emphasis on suddenness or snappiness. When unsure which adverb fits, this is usually the safe default.

Use 「早く」 for plain speed in doing or moving, 「パッと」 for a snappy action over in a flash, and 「急に」 when 'swiftly' really means something happens abruptly or without warning.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 急にきゅうにswiftly
• パッとsuddenly
• するするsmoothly
• すいすいlightly and smoothly (of movements)
• とうquickly
• 疾くとくquickly
• ガッとvigorously
• 快快的カイカイデhurriedly
• 早くはやくquickly