Where does “いい” come from?

いい (Japanese) comes from Japanese 良い, from Japanese よし, from Old Japanese よ, from Japanese 夜, from Old Japanese よる, from Proto-Japonic yoru, from Proto-Japonic yo — night.

いい (Japanese): good

Definitions

  1. good

Ancestry of “いい”, step by step

いい traces back through two separate lines of ancestry.

via Japanese 良い

StepLanguageWordMeaning
1Japanese良いgood; easy; enough; not wanted any more
2Japaneseよし縦し so-so; even if; 良し, 善し, 好し, 吉し, 佳し, 宜し all...
3Old Japanese
4Japanesenight, evening
5Old Japaneseよる
6Proto-Japonicyorunight
7Proto-Japonicyonight

via Chinese Mandarin

StepLanguageWordMeaning
1Chinese Mandarin
Every word from Proto-Japonic yoEvery word from Proto-Japonic yoruEvery word from Old Japanese よる
いい — Etymology, Origin & Word History | Etymology Explorer