Lack of knowledge; being unaware. Often used adverbially as '知らずに' (without knowing) or in expressions like '知らず知らず(のうちに)'.
彼は知らずに私のメモを捨ててしまった。
He threw away my notes without realizing it.
知らず知らずのうちに習慣になっていた。
It had become a habit before I even realized it.
彼女は知らせを待っていることを本人も知らずに外出した。
She went out without knowing that she was supposed to wait for the notice.
Used in the pattern '～は知らず' to mean 'I won't say about X' or 'aside from X, ...' — indicating that the speaker does not claim knowledge or responsibility for the first item while commenting on another.
彼の過去は知らず、今の仕事ぶりを評価したい。
I won't speak about his past; I want to judge him by his current work.
結果はどうなるかは知らず、まずは全力を尽くそう。
I don't know what the outcome will be, but let's do our best for now.
An archaic/literary conjunction placed at the start of a sentence meaning 'I know not whether...' or 'it is unknown if...'. Rare in modern spoken language.
知らずや彼が来るかどうかは、誰にも分からない。
Whether he will come or not is unknown to anyone.