困こまったちゃん

noun

person who is a pain without realizing it; oblivious nuisance

Colloquial, mildly mocking term for someone who causes trouble or irritation but seems unaware of it. Often used affectionately or in exasperation.

• 彼かれはまた遅ち刻こくして、本ほん当とうに困こまったちゃんだ。

  He's late again—what a pain, and he doesn't even realize it.

• あの困こまったちゃんには、何なん度ど言いっても伝つたわらない。

  No matter how many times you tell that oblivious nuisance, it never gets through.