auxiliary verb
without doing; not doing; not ... and
Classical continuative negative auxiliary. Attaches to the -nai stem of verbs (for サ変, せ～ず). Functions like 'without doing' or 'not ... and/so', often in formal or written language. See also ずに.
He left the room without saying anything.
auxiliary verb
Archaic sentence-ending negative, equivalent to modern ない. Rarely used in modern Japanese except in set phrases or classical contexts.
See also: ない
He left the room without saying anything.
Taking an exam without preparing is reckless.
The ぬ in 知らぬ is an old form, also expressed as 知らず.
It goes without saying that he is a genius.