(なん)

なんで
adverb
why, what for
1. why, for what reason
Used to ask the reason or cause for something.
(なん)だろう
I wonder why.
(なん)()なかった
Why didn't you come?
(なん)(おく)れた
Why were you late?
(なん)()いてる
Why are you crying?
Why would you say something like that?
2. how, by what means
Used to ask about the means or method.
(なん)()
What do you write with?
Asking about means/tools
What do you eat it with? — With chopsticks.
How are you getting there? — I'm going by train.
What did you make it with? — I made it with paper.
How do you get to school? — I go by bus.

USAGE: なんで is a casual way to ask "why" or "how." It's more informal than どうして or なぜ.

FORMALITY LEVELS:

  • なんで (casual - most common in spoken Japanese)
  • どうして (neutral)
  • なぜ (formal/written)

COMMON EXPRESSIONS:

NOTE: なんで can also mean "by what means" ((なに)で = with what), though context usually makes the meaning clear.