義弟

1. Origins, structure, and basic meaning

• Structure: 義弟 is read as ぎてい and is a noun for a younger male relative by marriage or a younger stepbrother.
• Basic usage: Specify the relation in 妹の夫である義弟, or use 年下の義弟ができる for a new stepfamily relationship.

2. Common pitfalls and similar expressions

• Do not fix it to one relationship
  • The sister’s husband is a brother-in-law, while a mother’s remarriage can create a younger stepbrother.
• Younger male relation
  • The 弟 element makes relative youth and male kinship central; it does not denote every male relative by marriage.