軽い
Japanese
    
| Kanji in this term | 
|---|
| 軽 | 
| かる Grade: 3 | 
| kun’yomi | 
| Alternative spelling | 
|---|
| 輕い (kyūjitai) | 
Etymology
    
From Old Japanese,[1] in turn from Proto-Japonic *karu. In Old Japanese, seldom used outside of proper nouns, where in the Kojiki it is spelled as 加流 and in the Man'yōshū it is spelled as 軽,[1][2] suggesting that this word was already used in Old Japanese with the meaning "light, lightweight". This might be weakly strengthened by a kana annotation of 軽 as karu(ku) in the Nihon Shoki.[1]
It is generally believed that karu(si) was the older form; this is also supported by Ryukyuan cognates (see Proto-Ryukyuan *karu). In the Heian period and Kamakura period, the variant かろし (karoshi) → かろい (karoi) has started to be in use, while 軽し (karushi) → 軽い (karui) has still seldom usage.
Later, both karosi and karusi began to be used in parallel. Then, in Early Modern Japanese, karui slowly began to replace karoi.
Pronunciation
    
- Tokyo pitch accent of inflected forms of "軽い"
| Source: Online Japanese Accent Dictionary | |||
| Stem forms | |||
|---|---|---|---|
| Continuative (連用形) | 軽く | かるく | [kàrúkú] | 
| Terminal (終止形) | 軽い | かるい かるい | [kàrúí] [kàrúꜜì] | 
| Attributive (連体形) | 軽い | かるい | [kàrúí] | 
| Key constructions | |||
| Informal negative | 軽くない | かるくない | [kàrúkúnáꜜì] | 
| Informal past | 軽かった | かるかった | [kàrúꜜkàttà] | 
| Informal negative past | 軽くなかった | かるくなかった | [kàrúkúnáꜜkàttà] | 
| Formal | 軽いです | かるいです | [kàrúꜜìdèsù] | 
| Conjunctive | 軽くて | かるくて | [kàrúꜜkùtè] | 
| Conditional | 軽ければ | かるければ | [kàrúꜜkèrèbà] | 
Adjective
    
Inflection
    
| Stem forms | |||
|---|---|---|---|
| Imperfective (未然形) | 軽かろ | かるかろ | karukaro | 
| Continuative (連用形) | 軽く | かるく | karuku | 
| Terminal (終止形) | 軽い | かるい | karui | 
| Attributive (連体形) | 軽い | かるい | karui | 
| Hypothetical (仮定形) | 軽けれ | かるけれ | karukere | 
| Imperative (命令形) | 軽かれ | かるかれ | karukare | 
| Key constructions | |||
| Informal negative | 軽くない | かるくない | karuku nai | 
| Informal past | 軽かった | かるかった | karukatta | 
| Informal negative past | 軽くなかった | かるくなかった | karuku nakatta | 
| Formal | 軽いです | かるいです | karui desu | 
| Formal negative | 軽くないです | かるくないです | karuku nai desu | 
| Formal past | 軽かったです | かるかったです | karukatta desu | 
| Formal negative past | 軽くなかったです | かるくなかったです | karuku nakatta desu | 
| Conjunctive | 軽くて | かるくて | karukute | 
| Conditional | 軽ければ | かるければ | karukereba | 
| Provisional | 軽かったら | かるかったら | karukattara | 
| Volitional | 軽かろう | かるかろう | karukarō | 
| Adverbial | 軽く | かるく | karuku | 
| Degree | 軽さ | かるさ | karusa | 
References
    
- Omodaka, Hisataka (1967) 時代別国語大辞典 上代編 [The dictionary of historical Japanese: Old Japanese] (in Japanese), Tōkyō: Sanseidō, →ISBN, page 234
-  “かる・い 【軽】”, in 日本国語大辞典 (Nihon Kokugo Daijiten, “Nihon Kokugo Daijiten”)   (in Japanese), 2nd edition, Tōkyō: Shogakukan, 2000, released online 2007, →ISBN, concise edition entry available here (Note: Dialectal meanings, etymological theories, pronunciation including modern, dialectal, and historical information, Jōdai Tokushu Kanazukai, historical dictionaries containing this word, and the kanji spellings in those dictionaries have been omitted.)  (in Japanese), 2nd edition, Tōkyō: Shogakukan, 2000, released online 2007, →ISBN, concise edition entry available here (Note: Dialectal meanings, etymological theories, pronunciation including modern, dialectal, and historical information, Jōdai Tokushu Kanazukai, historical dictionaries containing this word, and the kanji spellings in those dictionaries have been omitted.)
- Matsumura, Akira, editor (2006), 大辞林 [Daijirin] (in Japanese), Third edition, Tōkyō: Sanseidō, →ISBN
- NHK Broadcasting Culture Research Institute, editor (1998), NHK日本語発音アクセント辞典 [NHK Japanese Pronunciation Accent Dictionary] (in Japanese), Tōkyō: NHK Publishing, →ISBN
- Kindaichi, Kyōsuke et al., editors (1974), 新明解国語辞典 [Shin Meikai Kokugo Jiten] (in Japanese), Second edition, Tōkyō: Sanseidō