Translation guide
The English word 'imperfect' can describe something flawed, incomplete, or not perfect. In Japanese, the most natural translation depends on whether you're talking about a physical flaw, an incomplete action, a grammatical tense, or a philosophical concept. This guide covers the most common and useful ways to express these nuances.
Describing something that has a flaw, defect, or is not perfect in quality or condition.
The most direct and common translation for 'imperfect' when referring to something that is incomplete or flawed. Used for objects, systems, data, etc.
このシステムはまだ不完全だ。
This system is still imperfect.
不完全なデータに基づいて判断するのは危険だ。
It's dangerous to make decisions based on imperfect data.
Literally 'has a defect/flaw'. Stronger than 不完全, often used for manufactured products, designs, or when emphasizing a specific flaw.
この製品には欠陥がある。
This product is imperfect (has a defect).
Literally 'not perfect'. A softer, more conversational way to say something is imperfect. Often used about people or performances.
彼の演奏は完璧ではなかったが、感動的だった。
His performance was imperfect, but moving.
Means 'there is an inadequacy/defect'. Often used in formal contexts like reports or official documents to point out shortcomings.
報告書に不備がある。
The report is imperfect (has deficiencies).
Describing something that is not yet complete or fully developed.
Specifically means 'incomplete' or 'unfinished'. Used for projects, works of art, buildings, etc. that are not yet finished.
その絵は未完成のままだ。
The painting remains imperfect (unfinished).
未完成の交響曲
an imperfect (unfinished) symphony
A more conversational way to say 'not yet completed'. Emphasizes the ongoing nature of the incompleteness.
その計画はまだ完成していない。
The plan is still imperfect (not yet complete).
Referring to the imperfect tense or aspect in grammar, indicating an ongoing or repeated past action.
The technical term for 'imperfective aspect'. Used in linguistics.
日本語の「〜ていた」は未完了相を表すことがある。
Japanese '~te ita' can express the imperfect aspect.
Literally 'imperfect past', used in grammar discussions.
フランス語の半過去は未完了過去の一例だ。
The French imparfait is an example of the imperfect past.
Describing the inherent imperfection of humans, life, or the world, often with a positive or accepting nuance.
The noun form of 不完全, meaning 'imperfection'. Used to discuss the concept of imperfection as a quality.
人間の不完全さを受け入れることが大切だ。
It's important to accept human imperfection.
A more roundabout way to say 'imperfection', literally 'the fact of not being perfect'. Common in everyday speech.
完璧ではないことが、かえって魅力になることもある。
Imperfection can sometimes be charming.
Means 'fault' or 'weak point'. Used when talking about a person's imperfections or flaws.
不完全 (fukanzen) means 'imperfect' in the sense of flawed or lacking something necessary for perfection. 未完成 (mikansei) means 'incomplete' or 'unfinished', focusing on the state of not being finished. A painting can be 未完成 if the artist hasn't finished it, but it might not be 不完全 if what exists is flawless. Conversely, a finished product can be 不完全 if it has defects.
While you can say 不完全な人間 (imperfect human) in a philosophical sense, it's uncommon to call a specific person 不完全. Instead, use 欠点がある (has faults) or 完璧ではない (not perfect) to describe a person's imperfections more naturally.
誰にでも欠点はある。
Everyone has imperfections (faults).