Japanese Word Formation: Prefixes, Suffixes & Compounds — How to Break Down Long Words (N3-N2) [JLPT N3]
By Nihongo to Japan · Updated July 3, 2026
“不満足,” “美しさ,” “読み書き,” “書き込み” — a complete analysis of how Japanese new words are built
Japanese Word Formation: Prefixes, Suffixes & Compounds
Don't panic at an unfamiliar long word — Japanese has word-formation patterns you can break down: ① prefixes — added before a word to change meaning, like 「不満 (dissatisfied), 無関係 (unrelated), お茶 (beautifying)」; ② suffixes — added after a word, like 「美しさ (美しい ＋ さ = nominalizing), 音楽家 (expert), 子供たち (plural)」; ③ compounds — two words combined, like 「読み書き (read ＋ write), 書き込む (書く ＋ 込む)」. Master common affixes and compounding patterns, and you can infer the meaning of many new words.
🧠 Core idea: split a long word into ‘components' and the meaning emerges
The core is splitting a word into meaningful components (prefix/root/suffix) and inferring the whole: ① prefixes change or modify meaning — negation (不・無・非・未: 不可能, 無関係), beautifying (お・ご: お金, ご飯), emphasis (真・大: 真夜中, 大成功); ② suffixes change part of speech or add meaning — nominalizing (〜さ: 大きさ; 〜み: 楽しみ), profession/expert (〜家・〜者: 作家, 医者), plural (〜たち・〜ら), manner (〜的: 科学的); ③ compounds — verb stem ＋ verb (読み書き, 話し合う), noun ＋ noun, etc. Split a long word and the meaning becomes clear, without rote-memorizing each.
📌 Three Word-Formation Types
| Type | Pattern | Example |
|---|---|---|
| prefix | before a word, changes meaning | 不満・無料・お金 |
| suffix | after a word, changes part of speech/meaning | 美しさ・音楽家・科学的 |
| compound | two words combined | 読み書き・書き込む |
💬 Example Sentences (breakdown demo)
- 「不満」 = 不 (negative prefix) ＋ 満 (satisfied) → dissatisfied. — prefix (negation)
- 「美しさ」 = 美しい (adjective) ＋ さ (nominalizing suffix) → beauty (degree). — suffix (nominalizing)
- 「音楽家」 = 音楽 ＋ 家 (expert suffix) → musician. — suffix (profession)
- 「書き込む」 = 書き (ます-stem of 書く) ＋ 込む (enter) → write in, fill in. — compound verb
- 「読み書き」 = 読み (read) ＋ 書き (write) → literacy. — compound noun
🔄 Compare: prefix vs suffix vs compound / 不 vs 無
| Type | Position/Role | Example |
|---|---|---|
| prefix | before a word, changes/modifies meaning | 不・無・非・未・お・ご |
| suffix | after a word, changes part of speech/meaning | 〜さ・〜家・〜的・〜たち |
| compound | two words form a new word | 読み書き・話し合う |
⚠️ Common Mistakes
- Giving up at a long word: it can be split into prefix ＋ root ＋ suffix, inferred component by component.
- Negative prefixes have fixed pairings: 不・無・非・未 each have habitual collocations (✗ free combination) — memorize common words.
- Suffixes 〜さ/〜み: 〜さ mostly objective degree (大きさ); 〜み mostly subjective feeling (楽しみ, 痛み).
- Compound verbs take the ます-stem: 書き込む (書き ＋ 込む), the front part uses the ます-stem.
💡 Learning & When to Use
Japanese word formation has patterns: prefixes (like negation 不・無・非・未, beautifying お・ご) change/modify meaning; suffixes (like nominalizing 〜さ, profession 〜家, 〜的) change part of speech or add meaning; compounds (two words combined, like 読み書き, 書き込む). At an unfamiliar long word, split it into prefix ＋ root ＋ suffix and the meaning emerges, without rote-memorizing. Master common affixes and compounding patterns to infer many new words and speed up vocabulary growth. N3-N2.
🎯 JLPT Exam Tips
- High-frequency N3-N2: prefixes (不・無・非・未, お・ご), suffixes (〜さ・〜家・〜的・〜たち), compounds.
- Breakdown method: split a long word into prefix ＋ root ＋ suffix and infer each.
- Negative prefixes: 不・無・非・未 each have fixed collocations — memorize common combos.
🖊️ 練習題（5 題）
Q1. 「不満」の「不」の役割は？
(A) 接尾辞（後綴）
(B) 接頭辞（前綴）表示否定
(C) 複合語の前半
(D) 漢字の部首
Q2. 「美しさ」の造詞方法は？
(A) 接頭辞 + 詞
(B) 詞 + 接尾辞（〜さ）
(C) 名詞 + 名詞
(D) 動詞 + 動詞
Q3. 「書き込む」を分解すると？
(A) 書（書く）+ き込む
(B) 書き（書く的ます形）+ 込む（進入）
(C) 書 + き + 込 + む
(D) 書き + こむ（固有詞）
Q4. 「音楽家」の「家」の意味は？
(A) 房子
(B) 家族
(C) 職業・専門家を表す接尾辞
(D) 漢字の部首
Q5. 「不思議」と「無関係」の「不」と「無」の共通点は？
(A) 完全に同じ意味
(B) どちらも否定の接頭辞（前綴）
(C) 「不」は漢語、「無」は和語
(D) どちらも接尾辞
答案解析
1. (B) 接頭辞（前綴）表示否定 ── 「不満（不滿足）」= 不（否定前綴）+ 満（滿足）。「不〜」是漢語來源的否定前綴，放在漢語詞彙前表示否定：不安・不満・不思議。
2. (B) 詞 + 接尾辞（〜さ） ── 「美しさ（美麗）」= 美しい（形容詞）+ さ（接尾辞：名詞化）。〜さ 是把形容詞變成表示程度・性質的名詞的後綴。
3. (B) ── 「書き込む（書寫進去・填寫）」= 書き（書く的ます形去ます）+ 込む（進入的概念）。複合動詞：前動詞ます形 + 後動詞。
4. (C) ── 「音楽家（音樂家）」= 音楽（音樂）+ 家（か）。〜家（か）是表示「某領域的專家・從事者」的接尾辞：作家・画家・評論家・政治家。不是「房子・家族」的意思。
5. (B) ── 「不〜」和「無〜」都是否定的接頭辞，意思相近但使用有習慣：不満・不安・不思議（不+2字漢語）；無条件・無関係・無理（無+2字漢語）。具體選哪個是固定搭配，需要記憶。