Where does “朧雲” come from?

朧雲 (Japanese) comes from Japanese 朧, from Japanese 凡, from Middle Chinese 凡 — ordinary.

Ancestry of “朧雲”, step by step

朧雲 traces back through two separate lines of ancestry.

Step	Language	Word	Meaning
1	Japanese	朧	hazy, cloudy
2	Japanese	凡	mediocre, ordinary; mediocrity; dim, faint
3	Middle Chinese	凡	ordinary

Step	Language	Word	Meaning
1	Japanese	雲	a cloud; of how clouds are widely spread; of how...
2	Middle Chinese	雲	—