prim person; prude; stuck-up person
Describes someone who acts overly proper, reserved, or self-consciously refined, often with a hint of disapproval.
She's a prim person, always putting on airs of refinement.
あの澄まし屋には話しかけにくい。
That stuck-up person is hard to talk to.
Standard kanji spelling.
Common kana-kanji mixed spelling.
From the verb 澄ます (to put on airs) + 屋 (person with a certain trait).