なぜ

なぜ
noun
why
1. why, how come
Used to ask for the reason or cause of something.
なぜ()なかったの。
Why didn't you come?
なぜそう(おも)うのですか。
Why do you think so?
なぜ(おく)れたのか、理由(りゆう)(おし)えてください。
Please tell me the reason why you were late.
なぜそんなことを()ったのか、(いま)でも自分(じぶん)では()からない。
I still don't understand why I said such a thing.
なぜ日本(にほん)()たのかと()かれて、日本(にほん)文化(ぶんか)興味(きょうみ)があるからだと(こた)えた。
When asked why I came to Japan, I answered that it was because I was interested in Japanese culture.

なぜ asks for the reason or cause behind something.

FORMALITY:
More formal than どうして. Appropriate for writing, news, and formal speech.

FORMS:

  • Kanji: 何故(なぜ) (literary/formal)
  • なぜか: for some reason, somehow
  • なぜなら: because (used to introduce an explanation)

COMMON PATTERNS:

  • なぜ〜のか: why (embedded question)
  • なぜ〜かというと: the reason why... is
  • なぜ〜のですか: why? (polite)

SIMILAR WORDS:

  • どうして: more casual, also means "how"
  • なんで: colloquial, casual