adverb
(not) anything; (nothing) at all; (not) any
Used with a negative verb to emphasize a complete lack or absence. Stronger than 何も alone; often translates as 'nothing at all' or 'not a single thing'.
See also: 何も
冷蔵庫には何にも入っていない。
There is nothing at all in the fridge.
彼はそのことについて何にも知らなかった。
He knew absolutely nothing about that matter.