てしまう means completion and regret. It is a JLPT N4 Japanese grammar pattern used to show that an action is finished completely or happened with regret.
This grammar point often appears in daily conversation, stories, apologies, and JLPT N4 reading passages. If you want to say that something was completed or happened accidentally with an “oops” feeling, てしまう is a useful pattern to learn because it helps you read Japanese with more precision.
What does てしまう mean?
Use てしまう when you want to describe either full completion or an action the speaker feels bad about.
Natural translations include:
- do completely
- end up doing
- unfortunately do
The best translation depends on the sentence. Try to notice the writer’s or speaker’s purpose first, then choose the English phrase that fits that context.
How to form てしまう
Examples of the pattern:
- 食べてしまう
- 忘れてしまう
- 読んでしまう
The form before the grammar point matters. In JLPT questions, the wrong answer choices often use a similar meaning but attach it to the wrong type of word.
When is てしまう used?
Use てしまう in situations like:
- saying an action is completely finished
- expressing regret about a mistake
- describing an accidental or unwanted result
Tone and register:
- neutral; ちゃう and じゃう are casual contractions
- Common in conversation, narratives, apologies, and textbook examples
てしまう example sentences
After reading each sentence, ask what job てしまう is doing: completion, limitation, soft denial, or summarizing a conclusion. That makes the nuance easier to remember than a one-word translation.
Nuance of てしまう
The key nuance is completion plus possible regret, depending on context.
This matters because learners often translate advanced grammar too literally. A pattern may look simple, but it can signal the writer’s attitude, the scope of a rule, or the relationship between two ideas.
For example:
- In apologies or mistakes, it sounds regretful or apologetic.
- Compared with ちゃう・じゃう, it feels more complete and less casual.
てしまう vs ちゃう・じゃう
Both てしまう and ちゃう・じゃう can express related ideas, but they are different.
If both translations seem possible, check the tone. Is the sentence casual, formal, written, explanatory, or emotional? The tone often tells you which grammar point is natural.
Common mistakes with てしまう
A helpful practice method is to write one sentence with てしまう, then rewrite it with ちゃう・じゃう. If the meaning or tone changes, explain that difference in your own words.
Is てしまう on the JLPT?
Yes. てしまう is commonly taught as JLPT N4 grammar.
- recognize it in reading
- understand its nuance in context
- use it in simple original sentences
For test preparation, study the grammar point in full sentences. JLPT questions often test whether you understand the surrounding context, not just the dictionary meaning.
Practice questions for てしまう
Keep your first sentences simple. Once the structure feels natural, add more context so the nuance becomes clear.
Learning path for てしまう
Use てしまう as part of your JLPT N4 て-form action-flow and auxiliary verb grammar toolkit. Review the main て-form action first, then ask what the auxiliary adds: preparation, trial, completion, regret, movement, continuation, or a change over time. Build short verb chains before using longer sentences.
Related grammar to review next
- てしまう / ちゃう — compares another て-form auxiliary that changes action flow or completion.
- 終わる — compares another て-form auxiliary that changes action flow or completion.
- ておく — compares another て-form auxiliary that changes action flow or completion.
- てみる — compares another て-form auxiliary that changes action flow or completion.
Browse more lessons here:
Learn てしまう with Hane
If you want to review てしまう together with the related patterns above, Hane helps you practice Japanese in short, focused sessions.
Browse more lessons here:
FAQ about てしまう
What does てしまう mean in Japanese?
てしまう means “completion and regret” in Japanese. It is an N4 grammar point, and this lesson explains its formation, nuance, example sentences, common mistakes, and similar grammar.
Is てしまう on the JLPT?
てしまう is taught as N4 Japanese grammar in Hane's grammar lesson archive. Review it with examples, usage notes, and related N4 patterns.
How should I practice てしまう?
Read several example sentences, identify the form before and after てしまう, then make your own short sentences and compare it with nearby grammar points.