Unintended Actions

This is the first of many useful tools that will become essential in your day-to-day conversations. We will now learn how to express an action that has taken place unintentionally often with unsatisfactory results. This is primarily done by the verb 「しまう」. Let’s look at an example.


  1. 康介 【こう・すけ】 – Kousuke (first name)
  2. 宿題 【しゅく・だい】 – homework
  3. やる (u-verb) – to do
  4. しまう (u-verb) – to do something by accident; to finish completely

Kousuke: Did you do homework?

Alice: Oh no! (I screwed up!)

Using 「しまう」 with other verbs


  1. しまう (u-verb) – to do something by accident; to finish completely
  2. その – that (abbr. of それの)
  3. ケーキ – cake
  4. 全部 【ぜん・ぶ】 – everything
  5. 食べる 【た・べる】 (ru-verb) – to eat
  6. 毎日 【まい・にち】 – everyday
  7. キロ – kilo
  8. 太る 【ふと・る】 (u-verb) – to become fatter
  9. ちゃんと – properly
  10. 痩せる 【や・せる】 (ru-verb) – to become thin
  11. 結局 【けっ・きょく】 – eventually
  12. 嫌 【いや】 (na-adj) disagreeable; unpleasant
  13. こと – event, matter
  14. する (exception) – to do
  15. ごめん – sorry
  16. 待つ 【ま・つ】 (u-verb) – to wait
  17. 金魚 【きん・ぎょ】 – goldfish
  18. もう – already
  19. 死ぬ 【し・ぬ】 (u-verb) – to die

When 「しまう」 is used in this sense, it is normal to attach it to the te-form of another verb to express an action that is done or happened unintentionally. As is common with this type of grammar, the tense is decided by the tense of 「しまう」.

  1. そのケーキ全部食べてしまった
    Oops, I ate that whole cake.
  2. 毎日ケーキ食べて2キロ太ってしまいました
    I ate cake everyday and I (unintentionally) gained two kilograms.
  3. ちゃんと食べないと、痩せてしまいますよ。
    If you don’t eat properly, you’ll (unintentionally) lose weight you know.
  4. 結局ことさせてしまった
    In the end, I (unintentionally) made [someone] do something distasteful.
  5. ごめん待たせてしまって
    Sorry about (unintentionally) making you wait!
  6. 金魚もう死んでしまった
    The goldfish died already (oops).

Using the casual version of 「~てしまう


  1. しまう (u-verb) – to do something by accident; to finish completely
  2. 金魚 【きん・ぎょ】 – goldfish
  3. もう – already
  4. 死ぬ 【し・ぬ】 (u-verb) – to die
  5. 帰る 【かえ・る】 (u-verb) – to go home
  6. いい (i-adj) – good
  7. 皆 【みんな】 – everybody
  8. どっか – somewhere (abbr. of どこか)
  9. 行く 【い・く】 (u-verb) – to go
  10. そろそろ – gradually; soon
  11. 遅い 【おそ・い】 (i-adj) – late
  12. なる (u-verb) – to become
  13. また – again
  14. 遅刻 【ち・こく】 – tardiness
  15. する (exception) – to do
  16. ごめん – sorry
  17. つい – just (now); unintentionally
  18. お前 【お・まえ】 – you (casual)
  19. 呼ぶ 【よ・ぶ】 (u-verb) – to call

In casual speech, the 「~てしまう」 is often substituted by 「~ちゃう」 while 「~でしまう」 is substituted by 「じゃう」. Both 「~ちゃう」 and 「~じゃう」 conjugate just like regular u-verbs.

  1. 金魚もう死んじゃった
    The goldfish died already.
  2. もう帰っちゃっていい
    Is it ok if I went home already?
  3. みんなどっか行っちゃったよ。
    Everybody went off somewhere.
  4. そろそろ遅くなっちゃうよ。
    It’ll gradually become late, you know.

There is yet another very colloquial version of 「~てしまう」 and 「~でしまう」 where it is replaced by 「~ちまう」 and 「~じまう」 respectively. Unlike the cuter 「~ちゃう」 and 「~じゃう」 slang, this version conjures an image of rough and coarse middle-aged man.

  1. また遅刻しちまったよ。
    Darn, I’m late again.
  2. ごめんついお前呼んじまった
    Sorry, I just ended up calling you unconsciously.

Another meaning of 「しまう


  1. しまう (u-verb) – to do something by accident; to finish completely
  2. 宿題 【しゅく・だい】 – homework
  3. やる (u-verb) – to do

You may have noticed that 「しまう」 has another definition meaning “to finish something completely”. You may want to consider this a totally separate verb from the 「しまう」 we have covered so far. Occasionally but not usually, 「しまう」 will have this meaning rather than the unintended action.

  • 宿題やってしまいなさい
    Finish your homework completely.
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