義妹 ぎまい Also written いもうと Meanings Noun sister-in-law (spouse's younger sister or younger brother's wife) younger stepsister; younger adopted sister; non-blood-related younger sister Kanji 義 justice. Read as ギ. 妹 younger sister. Read as マイ. Example sentences メアリーはトムの義妹です。Mary is Tom's stepsister. Jinuma: Japanese Dictionary · Word lists