JLPT N3・N4 Prefix – Differences between “不” and “非”

Table of Contents

1. Differences between the prefix “不ふ” and “非ひ“
2. 不ふ
3. 非ひ
4. Let’s Compare
5. Summary
6. Quiz
7. Similar Articles
8. Comment

Q: What is the difference between the prefixes “不ふ” and “非ひ“when they come before a word?

A: The prefixes “不ふ” and “非ひ” serve to negate the following word. Here, we will briefly explain the differences in their usage.

不ふ (JLPT N4)

[Meaning]
① (Negation of the following word) … not do, … not be
② Not good

[Commonly Used Words]
① 不安ふあん(Unrest)・不満ふまん(dissatisfaction)・不ふ必要ひつよう(unnecessary)・不ふ完全かんぜん(incomplete)・不ふ合格ごうかく(failure)
② 不運ふうん(Bad luck)・不調ふちょう(poor condition)・不良ふりょう(defect)・不ふ安定あんてい(instability)・不ふ健康けんこう(poor health)　etc.

[Examples]
JLPTを受うけましたが不ふ合格ごうかくでした。(①)
I took the JLPT, but I failed.

明日あしたのプレゼンが不安ふあんで何なん回かいも練習れんしゅうしました。(①)
I was anxious about tomorrow’s presentation and practiced many times.

最近さいきんは不調ふちょうで仕事しごともうまくいきません。(②)
Recently, I’ve been feeling unwell, and work isn’t going well.

不ふ健康けんこうな食しょく生活せいかつを改あらためましょう。(②)
Let’s improve our unhealthy eating habits.

非ひ (JLPT N3)

[Meaning]
① (Negation of the following word) … not be, … lack
② Something that is not correct or does not conform to reason
③ To speak ill of someone

[Commonly Used Words]
① 非ひ効率こうりつ(Inefficiency)・非ひ常識じょうしき(lack of common sense)・非常ひじょう(emergency)・悲運ひうん(ill fortune)
② 非道ひどう(Inhumane)・非行ひこう(juvenile delinquency)
③ 非難ひなん(Criticism)　etc.

[Examples]
深夜しんや12時じに家いえでカラオケなんて非ひ常識じょうしきだ！(①)
Singing karaoke at home at midnight is outrageous!

息子むすこは非行ひこう少年しょうねんになってしまいました。(②)
My son has become a juvenile delinquent.

著名ちょめいなジャーナリストは非難ひなんをあびました。(③)
The prominent journalist faced criticism.

Let’s Compare

[不ふ]

This prefix indicates a simple negation similar to “not,” and it also represents a state or situation that is “not good.”

[Example ①]
不ふ必要ひつよう → 必要ひつようがない (not necessary)
学校がっこうに不ふ必要ひつようなものは持もって来こないでください。
Please do not bring unnecessary items to school.
⇒ This means not to bring items that are not needed at school (such as snacks or games).

不安ふあん → 安心あんしんがない (no sense of security)
明日あしたのプレゼンが不安ふあんで寝ねられないよ！
I’m so anxious about tomorrow’s presentation that I can’t sleep!
⇒ This indicates a lack of peace of mind about the presentation tomorrow (i.e., feeling worried).

[Example ②]
不運ふうん → 運うんが悪わるい (Bad luck)
不運ふうんにも交通こうつう事故じこにあって1か月げつも入院にゅういんをしました。
Unfortunately, I was in a car accident and had to stay in the hospital for a month.
⇒ It means that due to bad luck, I was involved in a car accident.

［不ふ+Adjectives］

It tends to be used with comparative adjectives.

[Commonly Used Adjectives]
必要ひつような(necessary)・透明とうめいな(transparent)・自由じゆうな(free)・得意とくいな(good at)など

[Examples]]
不ふ透明とうめい → 透明とうめいではないもの (not transparent)
荷物にもつは不ふ透明とうめいなものに入いれないでください。
Please do not put the items in opaque containers.

不ふ得意とくい→得意とくいではない (not good at)
弟おとうとは数字すうじが不ふ得意とくいです。
My younger brother is not good with numbers.

---

[非ひ]

There are several meanings for this.

The first meaning is that it refers to something that does not apply, is other than, or deviates from a certain state in relation to nouns and adjectives.

The second meaning indicates more than simple negation; it expresses that the original or proper state has disappeared and resulted in a bad condition. Depending on the context, “the original state” may also refer to moral or ethical standards.

Finally, the third meaning is “to speak ill of someone.”

[Examples ①]
非ひ日常にちじょう → 日常にちじょうから外はずれている (deviating from the ordinary)
海外かいがいでの生活せいかつは非ひ日常にちじょう的てきな感かんじがします。
Living abroad feels unusual.

[Example ②]
非ひ効率こうりつ → 効率こうりつが悪わるい (inefficient)
こんな非ひ効率こうりつなやり方かたやめて効率こうりつのいいやり方かたを考かんがえよう！
Let’s stop using such an inefficient method and think of a more efficient way!
⇒ This means stopping using a method that is not effective and considering a better approach.
*The term “不ふ効率こうりつ” does not exist. “効率こうりつ” means “the results or outcomes obtained relative to the time and effort spent.” Therefore, “非ひ” is used to indicate a deviation from the optimal state.

非行ひこう → 行おこないが非常ひじょうに悪わるい (delinquent behavior)
兄あには非行ひこう少年しょうねんになって家出いえでをしました。
My older brother became a juvenile delinquent and ran away from home.
⇒ This describes how my brother changed from a good boy into a very bad person.

[例れい③]　
非難ひなん →相手あいての悪わるいところを責せめること (criticism)
この俳優はいゆうは世界せかいから非難ひなんされて、ついに俳優はいゆうを辞やめてしまいました。
This actor was criticized by the world and eventually quit acting.
⇒ This means that the actor was spoken of negatively by people worldwide.

［非ひ+Nouns］

The prefix “非ひ” is often used with nouns, and when followed by adjectives, it tends to be used with the suffix “的てきな”.

[Commonly Used Nouns]
公開こうかい(to make it public)・日常にちじょう的てきな(everyday)・現実げんじつ的てきな(reality)・国民こくみん的てきな(national)　など

[Examples]
非ひ公開こうかい → 公おおやけに公開こうかいされていないこと(not publicly disclosed)
この情報じょうほうは非ひ公開こうかいです。
This information is confidential.

非ひ現実げんじつ → 現実げんじつから外はずれている・離はなれていること(deviating from reality)
日本にほんでの生活せいかつは非ひ現実げんじつ的てきで、夢ゆめを見みているようだ。
Living in Japan feels unreal like I’m dreaming.

非ひ国民こくみん → 国民こくみんである本来ほんらいの姿すがたから外はずれていること(deviating from the ideal of being a citizen)
そんな考かんがえ方かたは非ひ国民こくみん的てきだよ。
That kind of thinking is unpatriotic.

Summary

[不ふ]

• ①Simple negation
• ②Indicates a bad state or situation.
• Often used together with な-adjectives.

[非ひ]

• ①Does not apply to that, is other than that, or deviates from a certain state.
• ②The original state or proper form is lost, resulting in a bad condition.
• ③To speak ill of someone.
• Often used together with nouns.

Quiz

Read the following sentence and choose the expression that fits the context from the options provided in the parentheses.

Click on the question to check the answer.

---

---