大人おとな買がい

noun, noun or participle which takes 'suru', transitive verb

buying in bulk like an adult; splurging on collectibles

Colloquial term for buying a large quantity of items typically marketed to children (e.g., manga, trading cards, snacks) all at once, as only an adult with disposable income could. Often used humorously or self-deprecatingly.

• 新しん刊かんの漫まん画がを全ぜん巻かん大人おとな買がいした。

  I bought the entire series of the new manga in one go.