Meaning & Usage
✨ Basic Meaning
To fit, to match, to suit, to be correct, to agree, or (as a suffix) to do something mutually/reciprocally.
🎯 Primary Function
To express a state of harmony, correctness, compatibility, or mutual action.
📋 Grammar Structure
Verb (Stem/Masu-form) + 合う
Noun + が + 合う (A noun is correct/matches)
Noun + に + 合う (To suit a noun)
合う → 合わない (あわない) / V-masu + 合わない
🎭 Usage Contexts
Formal Situations
Used in formal settings, especially the V-合います form (e.g., “ご意見を話し合いましょう” – Let’s discuss our opinions).
Informal Situations
Very common in casual conversation (e.g., “気が合うね” – We get along well).
Written Language
Commonly found in instructions, formal documents, and literary texts, especially V-合う structures.
Spoken Language
Highly frequent, both as a stand-alone verb and a reciprocal suffix.
💡 Common Applications
Expressing Suitability or Fit (Intransitive)
Used to indicate that one thing (size, color, style, job) is appropriate for, or matches, another thing or person. Uses the particle に or と.
Example: この仕事は私の能力に合っている。 (Kono shigoto wa watashi no nōryoku ni atte iru.)
Indicating Correctness (Intransitive)
Used when something (a calculation, an answer, a clock) is determined to be accurate or right. Uses the particle が.
Example: 計算の結果が合っているか確認する。 (Keisan no kekka ga atte iru ka kakunin suru.)
Reciprocal Action (Suffix: V-合う)
Attached to the stem of a verb (V-masu form) to show that the action is performed mutually or reciprocally by two or more parties. This is a common N3/N2 pattern.
Example: お互いの意見を話し合う。 (Otagai no iken o hanashiau.)
Frequency
High. It is a fundamental verb and a highly productive suffix.
Difficulty
Intermediate (JLPT N3) – The base meaning is simple, but the reciprocal suffix is essential for advanced communication.
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Example Sentences
Example #1
このジャケットの色とズボンが合っていますね。
Furigana: このジャケットのいろとズボンがあっていますね。
Romaji: Kono jaketto no iro to zubon ga atte imasu ne.
English: The color of this jacket and the pants match well.
Example #2
私たちは趣味が合うので、話が尽きない。
Furigana: わたしたちはしゅみがごうので、はなしがつきない。
Romaji: Watashitachi wa shumi ga au no de, hanashi ga tsukinai.
English: We have similar hobbies, so we never run out of things to talk about.
Example #3
靴を履いて、サイズが合うか試してみてください。
Furigana: くつをはいて、サイズがごうかためしてみてください。
Romaji: Kutsu o haite, saizu ga au ka tameshite mite kudasai.
English: Please try on the shoes to see if the size fits you.
Example #4
答えをチェックしたら、計算が全部合っていた。
Furigana: こたえをチェックしたら、けいさんがぜんぶあっていた。
Romaji: Kotae o chekku shitara, keisan ga zenbu atte ita.
English: When I checked the answers, all of my calculations were correct.
Example #5
困ったときは、お互いに助け合いましょう。
Furigana: こまったときは、おたがいにたすけあいましょう。
Romaji: Komatta toki wa, otagai ni tasukeaimashou.
English: In times of difficulty, let’s help each other.
Example #6
重要な決定は、家族と話し合って決めるべきだ。
Furigana: じゅうようなけっていは、かぞくと話しあってきめるべきだ。
Romaji: Jūyōna kettei wa, kazoku to hanashiatte kimeru beki da.
English: Important decisions should be made after discussing them with family.
Example #7
病気についての医師の意見は、私の意見とは合わなかった。
Furigana: びょうきについてのいしきのいけんは、わたしのといけんとはごわなかった。
Romaji: Byōki ni tsuite no ishi no iken wa, watashi no iken to wa awanakatta.
English: The doctor’s opinion on the illness did not agree with mine.
Example #8
そのメガネはあなたの顔によく合っていますね。
Furigana: そのメガネはあなたの顔によくあっていますね。
Romaji: Sono megane wa anata no kao ni yoku atte imasu ne.
English: That style of glasses really suits your face.
Example #9
彼女と目が合った瞬間、ドキッとした。
Furigana: かのじょと めがごうたしゅんかん、ドキッとした。
Romaji: Kanojo to me ga atta shunkan, doki’ to shita.
English: The moment our eyes met, my heart skipped a beat.
Example #10
この料理は私の口に合わない。
Furigana: このりょうりはわたしのくちにごわない。
Romaji: Kono ryōri wa watashi no kuchi ni awanai.
English: This dish doesn’t agree with my taste/diet.
Notes & Nuances
📌 Important Points
Idiomatic Expressions
This is an important idiomatic expression meaning ‘to get along well’ or ‘to be compatible,’ literally ‘spirits/temperaments match.’
Example: 気が合う (Ki ga au)
Reciprocal Function (V-合う)
As a reciprocal suffix, the V-masu + 合う structure emphasizes that the action is performed *mutually* between two or more subjects. This is different from simply doing the action to someone else.
Example: 見合う (Miau – look at each other), 助け合う (Tasukeau – help each other)
Fixed Phrases for Taste
Means ‘to suit one’s taste/diet.’ Often used negatively to politely decline food: “私の口にはちょっと合いません” (It doesn’t quite suit my taste).
Example: 口に合う (Kuchi ni au)
⚠️ Common Mistakes
❌ 友人と服が合いました。 (Tomodachi to fuku ga aimashita.) – Should mean “The clothes fit my friend,” but might be mistakenly used for “I met my friend.”
✅ Use 会う (あう) for meeting a person. Use 合う (あう) for fitting, matching, or reciprocal action.
A common error is confusing the kanji: 会う means ‘to meet a person/friend,’ while 合う means ‘to match, agree, or join.’
❌ 色が合うね。 (Iro ga au ne.) – If trying to say ‘The colors match well with each other,’ using と might be clearer: “色と色が合うね” or “色がよく合っているね.”
✅ Ensure proper particle usage: Nounが合う for correctness/fit, Nounに/と合う for compatibility. V-masu + 合う for reciprocal action.
Particle usage changes the nuance. For example, “服が合う” (The clothes fit) vs. “服に合う” (To match the clothes).
🏛️ Cultural Context
Politeness Level: Neutral/Standard. The politeness is determined by the conjugation (-ます/-ました, etc.), not the verb itself. V-合う is standard.
Social Situations: The reciprocal form (V-合う) is crucial for expressing cooperative social actions, emphasizing teamwork, cooperation, and mutual understanding.
Regional Variations: The verb’s meaning is standard across Japan. However, some regional dialects might use different verbs for ‘fit’ or ‘agree.’
🔍 Subtle Differences
合う (Au) vs. 適する (Tekisuru)
合う is generally used for a literal or emotional fit (size, color, personality). 適する means ‘to be suitable/appropriate’ in a formal or objective sense (e.g., This room is suitable for meetings).
When to use: Use 合う for daily situations, clothing, tastes, and agreement. Use 適する for formal suitability or when stating qualifications.
合う (Au) vs. 一致する (Icchi suru)
合う is broad (fit, correct, agree). 一致する specifically means ‘to coincide,’ ‘to be in agreement,’ or ‘to be the same’ (e.g., data, opinions, dates).
When to use: Use 合う for general correctness or matching. Use 一致する when emphasizing that two separate pieces of information are identical.
📝 Conjugation Notes
合う is a Godan (Group 1) verb. The stem (masu-form) is 合い (ai). When used as a suffix for reciprocal action (V-合う), it attaches to the V-masu stem: 話す → 話し合いましょう。 (Hanashi-ai-mashou).
🔊 Pronunciation Tips
The sound あう (au) is pronounced as a smooth glide, almost like a long ‘a’ followed by a slight ‘ooh’ sound, avoiding a strong pause between ‘a’ and ‘u.’ In V-合う constructions, the ‘i’ from the V-masu stem (e.g., hanashi + au) merges: ‘hanashiau’ (not ‘hanashi-au’).
🧠 Memory Tips
To remember the kanji 合: visualize two things fitting together (like two boxes joining). Think of the reciprocal function V-合う as two people or things ‘joining’ in the action.
Other Grammar
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