not knowing at all; completely unaware; without the slightest idea
Used in negative contexts to emphasize total lack of knowledge or awareness. Often appears with verbs like 思う, 考える, or 知る in negative form.
I had no idea at all that he was thinking such a thing.
We parted as usual, completely unaware that it would be our last conversation.
Standard kanji spelling; 露 is an ateji for つゆ meaning 'a little bit'.
Mixed kana-kanji spelling; common in modern writing.
From 露 (つゆ, 'a little bit') + 知らず (しらず, 'not knowing'). The kanji 露 is ateji; the phrase literally means 'not knowing even a little'.