何(なん)でも

何(なん)でも combines 何(なに) with the particle でも, giving "whatever it may be". It has two quite different uses.

ANYTHING / EVERYTHING (sense 1):

• 何(なん)でも食(た)べる (eat anything)
• 何(なん)でもいい (anything is fine)
• 何(なん)でも知(し)っている (know everything)

With a negative verb the meaning flips to "nothing", but Japanese uses 何(なに)も for that, not 何(なん)でも.

HEARSAY (sense 2):
Sentence-initial, and normally followed by らしい or そうだ at the end:

• 何(なん)でも〜らしい / そうだ (I hear that ~)

It marks the whole sentence as secondhand and slightly vague - the speaker is passing on what they heard without vouching for it. A comma after 何(なん)でも is usual in writing.

Watch out

何(なん)でも on its own does NOT mean "by all means" or "at any cost". That is the fixed expression 何(なに)が何(なん)でも, which needs the full four-element form: 何(なに)が何(なん)でも勝(か)ちたい (I want to win no matter what), not ×何(なん)でも勝(か)ちたい. どうしても is a close everyday equivalent.

Related words

• 何(なに)も (nothing - with a negative)
• 何(なに)か (something)
• 何(なん)でもかんでも (anything and everything, indiscriminately - emphatic, often disapproving)
• 何(なん)でもない (it's nothing, no big deal)
• 誰(だれ)でも (anyone), いつでも (anytime), どこでも (anywhere) - the same 〜でも pattern on other question words