しまう (shimau) Meaning Japanese Grammar - Do Something By Mistake

Author Anna Baffa Volpe for article 'しまう (shimau) Meaning Japanese Grammar - Do Something By Mistake'

Anna Baffa Volpe

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しまう (shimau) Meaning Japanese Grammar - Do Something By Mistake

Using the te form of the verb combined with the verb しまう (which means finish) we express an action that is been done by mistake, completely, or unfortunately.


These meanings derive from the verb しまう, which can express:

  • The fact of having completed something: this meaning expresses the achievement of a goal in a perfect or optimal way
  • Expressing regret in having performed a certain action: indicates a sense of surprise and displeasure at the result of an action performed, which in the end proved to be wrong

The preposition stated before the use of しまう must be an action that has already been completed and completed. When しまう expresses regret, the regret must be for an action that has already ended, so it is no longer possible to return back

Expressing regret with しまう


There is nothing you can do about something that has already happened (unintentionally).

In this example we see how the use of 起きてしまった indicates regret for something that has already happened. The verb ()きる in this context means to happen.

By adding the te form and the verb しまう it expresses that what happened was unintentional.


In fact, if we had only used the verb ()きる, the sentence would simply state an action happened in the past, without any additional indication (simply telling what happened).

With the addition of しまう, on the other hand, the sentence expresses a nuance that the result of the action was unexpected or that it was not our intention to happen.

For this reason, using しまう gives much more emphasis to the sentence (even if the translation remains the same)

This is an example in which the Japanese language is able to express additional information with respect to the translation.


Oh no! I forgot to bring my homework!

The use of the term しまった indicates something that unfortunately has not been done. A translation of this expression can be simply oh no.

Action done completely with しまう


I have finished writing my report.

As mentioned, the form しまう can also be used to indicate the fact that an action has been completed. In this example we see how the verb 書く (write) conjugated with しまう indicates having finished writing (completely).


I forgot my notebook.

Also in this example we see how しまう expresses an action performed by mistake and with regret. A possible literal translation could be How unfortunate! I forgot my notebook.

Colloquial forms of しまう: ちゃう and じゃう

There are two more colloquial forms of the verb しまう: ちゃう and じゃう.

ちゃう and じゃう are used much more often in the spoken language.

The use of ちゃう or じゃう depends on the conjugation of the te form of the verb:

  • If the verb ends in te (て), then ちゃう is used
  • If the verb ends in te (で), then じゃう is used


The dog is completely mad.


I have (completely) finished reading that book.

ちゃう in an informal conversation between Senpai and Kōhai





Tōno kun






What's that? A love letter?



That's not it.



Sorry for having asked you to do all that.



No problem, I finished quickly.



Thanks. So, is it true that you'll be transferring schools?



Yes, at the end of the year.



Where to?




Senpai (せん)(ぱい) and Kōhai (こう)(はい)

The Kōhai / Senpai system means that older students (senpai) lead and advise younger students (kohai). The kohai use polite language towards the senpai, different from the form of speaking they use with their other friends. The Kōhai, in turn, becomes the Senpai to younger students. In the dialogue Tōno kun uses the polite form ます while Senpai uses colloquial and short expressions towards him.

Colloquial form ちゃう wih the verb する

  • (ねが)いする o-negai suru, ask a favour in the informal expression becomes お(ねが)いしちゃう and in its て form ⇨お(ねが)いしちゃって
  • (てん)(こう)する tenkō suru change of school(てん)(こう)しちゃう ⇨ (てん)(こう)しちゃって