so what?; who cares?
A blunt, dismissive response to a statement, implying that the speaker finds the preceding point irrelevant or unconvincing. Often used in arguments or casual retorts.
「遅刻したのは電車が遅れたからだよ。」「だから何だ。言い訳は聞きたくない。」
"I was late because the train was delayed." "So what? I don't want to hear excuses."
「彼はお金持ちなんだって。」「だから何だ。性格が悪ければ意味がない。」
"I heard he's rich." "Who cares? If his personality is bad, it doesn't matter."
A fixed phrase combining だから ('therefore') with 何だ ('what is it?'), literally 'so what is it?'. The expression has become idiomatic as a dismissive retort.