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.

康介：宿題をやった？
Kousuke: Did you do homework?

アリス：しまった！
Alice: Oh no! (I screwed up!)

Using 「しまう」 with other verbs

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. そのケーキを全部食べてしまった。
   Oops, I ate that whole cake.
2. 毎日ケーキを食べて、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、嫌なことをさせてしまった。
   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. 金魚がもう死んでしまった。
   The goldfish died already (oops).

If you want to see many more examples, look up 「しまう」 on WWWJDIC and click the [EX] link. There are over 100 examples with translations for you to enjoy.

Using the casual version of 「～てしまう」

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. 金魚がもう死んじゃった。
   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 a 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、ついお前を呼んじまった。
   Sorry, I just ended up calling you unconsciously.

Another meaning of 「しまう」

If you look up 「しまう」, the edict dictionary will say:
仕舞う 【しまう】 (v5u) (uk) to finish; to close; to do something completely; to put away; to put an end to;
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.

• 宿題をやってしまいなさい。
  Finish your homework completely.