[Pronunciation] [rí bó x and shā n]
[explanation] thin: approaching. The sun is going down. Metaphor is that people are aging or things are decaying and dying.
[Source] "Bear Biography": "When you are in Miluo, you will fall; I am afraid that the sun is thinner than the western hills. "
Nowadays, the colonial system is dying.
I'm getting thinner, I'm dying, people's lives are in danger, and the river is getting worse.
[antonym] Spring and Autumn Period, it's time to come out.