🦅 Project Eagle
Quadruple VS

Synonym Boundary: "する", "なさる", "〜てしまう", "敝蓋不棄"

All represent the core concept "do", but require precise selection.

Japanese Option A

する

する (suru)
N5 / CEFR
Japanese Option B

なさる

なさる (nasaru)
N4 / CEFR
Japanese Option C

〜てしまう

〜てしまう (te shimau)
N3 / CEFR
Japanese Option D

敝蓋不棄

へいがいふき
C2PLUS / CEFR

Quadruple VS Nuance Contrast & Social Differences

When expressing "do" in Japanese, you must carefully distinguish between "する", "なさる", "〜てしまう", "敝蓋不棄" based on context.
  • する (する (suru) - Level: N5): Maps to "to do, to make" and is used when A very versatile verb. Polite form is します.
  • なさる (なさる (nasaru) - Level: N4): Maps to "to do (honorific form of する)" and is used when Honorific form of する.
  • 〜てしまう (〜てしまう (te shimau) - Level: N3): Maps to "to do completely; to do regrettably/unintentionally" and is used when Expresses either the completion of an action, often implying 'finished doing,' or an action done unintentionally or regrettably. In casual speech, it's often shortened to 〜ちゃう/〜じゃう.
  • 敝蓋不棄 (へいがいふき - Level: C2PLUS): Maps to "do not discard a worn-out lid; a metaphor for valuing old things or long-standing friendships" and is used when Essential structural term in CEFR C2PLUS vocabulary syllabus..
Mixing these up can easily lead to unnatural translations. Refer to the bilingual context cards below to master the boundaries!
Context for "する"
毎日日本語を勉強します。
I study Japanese every day.
Context for "なさる"
先生は何をなさいますか。
What will the teacher do?
Context for "〜てしまう"
大事な書類をなくしてしまいました。
I accidentally lost important documents.
Context for "敝蓋不棄"
私は敝蓋不棄に興味があります。
I am interested in do not discard a worn-out lid; a metaphor for valuing old things or long-standing friendships.

Synonym Mastery Challenge

Which Japanese word perfectly fits this blank space?

Fill in the blank: "毎日日本語を勉強します。" (Meaning: "I study Japanese every day.")
🎉 Correct Answer!

Remember: "する" is correct here because it represents "to do, to make" in the context: "I study Japanese every day.".

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