clear, bright, distinct
朖 centers on clarity and brightness: something clear, bright, or distinct. The meanings all point to a state of being easily perceived or understood.
朖 combines 月 (moon) with 良, which likely contributes the sound and may reinforce the idea of brightness or goodness. The exact historical development is uncertain.
The moon 月 on the left and 良 (good) on the right suggest a good, bright moon that makes everything clear and distinct.
For ロウ, imagine a low, bright moon casting clear light: low -> ロウ, and the moon makes the night distinct.