Unconsciously; unwittingly; without realizing it — often used in the phrase '知らず知らずのうちに'.
知らず知らずのうちに時間が過ぎてしまった。
Time passed without my realizing it.
忙しくて、知らず知らず夜遅くまで働いてしまった。
I was so busy that I unknowingly worked until late at night.
知らず知らず彼の影響を受けて考え方が変わっていた。
Without realizing it, my way of thinking had been influenced by him.