noun, na-adjective
idiot; stupid person; stupidity
Colloquial and mildly derogatory term for a foolish person or stupidity. Often used in casual, sometimes affectionate, banter.
あいつは本当にぽんつくだな。
That guy is a real idiot.
そんなぽんつくなこと言うなよ。
Don't say such stupid things.