なおす (直す・治す): One Verb, Many Meanings (with Examples)
One sound, several kanji
なおす is a classic Japanese homophone: one pronunciation, two kanji, two jobs. The good news is that the two meanings live in completely different worlds, so once you know which kanji belongs to which, you'll almost never mix them up.
- 直す — for things, mistakes, and conditions: a broken clock, a wrong answer, a messy room.
- 治す — for the body: a cold, a fever, a broken leg. Notice 治 also appears in 治療 (ちりょう, "medical treatment") — that's your hint that 治 = healing.
Both share one underlying idea: something is out of order, and you return it to how it should be. A broken watch should tick; a wrong answer should be right; a sick body should be well. You're "putting it right." Hold that image and the split below is easy: 直 puts objects and mistakes right, 治 puts the body right.
There's also a third, very useful なおす — the helper verb 〜直す, which attaches to other verbs to mean "do it again / do it over." We'll cover that too.
The meanings, most common first
1. To fix / repair (直す)
ヤッタンは壊れた時計を直した。
ヤッタンは こわれた とけいを なおした。
Yattan fixed the broken clock.
2. To correct / put right (mistakes) (直す)
先生はヤッタンの間違いを直してくれた。
せんせいは ヤッタンの まちがいを なおして くれた。
Sensei corrected Yattan's mistakes for me.
間違いを直す = to correct a mistake. Very common in class and at work.
3. To cure / heal (an illness) (治す)
この薬は風邪を治す。
この くすりは かぜを なおす。
This medicine cures a cold.
治す uses 治 because it's about the body, not objects.
4. To heal (an injury) (治す)
モチは早くけがを治したいと言った。
モチは はやく けがを なおしたいと いった。
Mochi said he wants to heal his injury quickly.
5. To redo / do over (〜直す, helper verb)
ヤッタンはレポートを書き直した。
ヤッタンは レポートを かきなおした。
Yattan rewrote the report.
書く + 直す → 書き直す = rewrite. Attach 〜直す to a verb stem for 'do it again.'
6. To start over / try again (やり直す)
間違えたので、ヤッタンは最初からやり直した。
まちがえたので、ヤッタンは さいしょから やりなおした。
Since he made a mistake, Yattan started over from the beginning.
やり直す (やる + 直す) = to do over. A super-handy everyday word.
7. To tidy / put back in order (直す)
ヤッタンの弟は部屋を直した。
ヤッタンの おとうとは へやを なおした。
Yattan's little brother tidied up his room.
In western Japan 直す can even mean 'to put away.' Standard meaning: set right / tidy.
The pattern under all of these is the same: return something to its proper state. 直す sets objects, mistakes, and order right; 治す sets the body right; 〜直す means "do the action right, again."
Common collocations worth memorizing
Learn these as fixed chunks and you'll pick the right kanji automatically:
| Collocation | Meaning | Kanji |
|---|---|---|
| 時計を直す | to fix a clock | 直 |
| 間違いを直す | to correct a mistake | 直 |
| 故障を直す | to repair a breakdown | 直 |
| 病気を治す | to cure an illness | 治 |
| 風邪を治す | to cure a cold | 治 |
| けがを治す | to heal an injury | 治 |
| 書き直す | to rewrite | 直 (helper) |
| やり直す | to redo / start over | 直 (helper) |
Kanji & related verbs
- 直す writes "fix / correct / put right" — objects, mistakes, order. The kanji 直 also reads ちょく / じき and carries the sense of "straight, direct, set right."
- 治す writes "cure / heal" — anything to do with the body. The kanji 治 reads じ / ち and appears in 治療 (ちりょう, treatment) and 政治 (せいじ, politics, "to govern/set in order").
- 〜直す as a helper verb is written with 直 and means "redo": 書き直す (rewrite), やり直す (start over), 読み直す (reread), 考え直す (rethink).
The big one to flag is the intransitive partner なおる (直る・治る) — same kanji split, but it means things happen on their own. That's the section below.
なおす vs なおる — the transitive/intransitive pair
なおす is transitive (someone fixes/cures something). Its twin なおる is intransitive (something gets fixed / gets better by itself). The JLPT loves testing this, and the kanji split (直 vs 治) carries straight across both.
| Form | Core idea | Example |
|---|---|---|
| なおす (直す・治す) — transitive | Someone does it to something: fix it / cure it | ヤッタンが故障を直す = Yattan fixes the breakdown |
| なおる (直る・治る) — intransitive | It gets fixed / gets better on its own | 故障が直る = the breakdown gets fixed |
The quick test: with なおす you can point to the person doing it (and the object takes を); with なおる the thing just changes state (it takes が). Body version too: 風邪を治す = "I cure the cold" vs 風邪が治る = "the cold gets better." Keep the kanji rule in both: 直 for objects/mistakes, 治 for the body.
Quick recap
- 直す = fix / repair / correct (objects, mistakes, order). 治す = cure / heal (the body). Same sound, different kanji.
- Hint: 治 lives in 治療 (treatment) → it's the body / illness one.
- 〜直す attaches to a verb to mean "do it again": 書き直す, やり直す.
- It's a transitive う-verb; its intransitive partner is なおる (直る・治る), which takes が.
Your turn
Ready to test your N5 vocabulary in context?
Start the 5-question drill →Frequently asked questions
What is the difference between 直す and 治す?
They sound identical (なおす) but split by topic: 直す is for fixing objects, correcting mistakes, and putting things in order; 治す is for curing illness and healing injuries. Tip: 治 also appears in 治療 (medical treatment), so 治 = the body.
Is なおす a ru-verb or u-verb?
なおす is a Group 1 (う-verb / godan) verb: なお-す → なおし-ます, なおし-て, なおさ-ない. It conjugates like 話す.
What does 〜直す mean attached to a verb?
It means 'do the action again / over.' Attach 直す to a verb stem: 書く → 書き直す (rewrite), やる → やり直す (start over), 読む → 読み直す (reread).
What is the difference between なおす and なおる?
なおす is transitive — someone fixes or cures something (故障を直す, 風邪を治す). なおる is intransitive — something gets fixed or gets better on its own (故障が直る, 風邪が治る). The same 直 vs 治 kanji rule applies to both.