sister complex; excessive attachment to one's sister
Refers to an unusually strong emotional dependence on or obsession with one's sister, often used in psychological or colloquial contexts. Similar in construction to 'mother complex' (マザーコンプレックス).
He has a sister complex and couldn't wholeheartedly celebrate his younger sister's marriage.
When someone has a strong sister complex, they may feel jealous if their older sister gets a boyfriend.
Variant with interpunct; less common in running text.
Loanword from English 'sister complex', modeled after psychological terms like 'Oedipus complex'.