Search gender: all male female Koyoi Boy Name Meaning, Kanji Variations. 1 names found. gender: all male female Name: koyoi Katakana: コヨイ 0 Kanji: 小宵 Meaning: 小Small. Little. Small in number or quantity. Trivial. Insignificant. Unimportant. Young person. Underestimate the ability. To treat lightly. A word used to humble oneself. 宵Evening. Night. It was just after dark. You can save your favorite names with NAZUKE PON > About Japanese Names > Search For Japanese Names > Koyoi Boy Name Meaning, Kanji Variations.