before, preceding, earlier, former, past, previously
曩 centers on a point in time that has already passed: something before, earlier, or in the past. It refers to a former state or a preceding moment.
曩 combines 日 (sun/day) with 襄, which likely contributes the sound and possibly the idea of past time. The exact historical development is uncertain.
The sun 日 sits above 襄, like a sun that has already set behind a complex shape, marking something that happened before.
For ノウ, imagine a person nodding 'no' to the past: 'No, that was before.' The sound 'no' cues ノウ while the sun sets on earlier times.