Where does “酸い” come from?

酸い (Japanese) comes from Japanese 酢, from Middle Chinese す.

酸い (Japanese): vinegary, sour

Definitions

vinegary, sour

Ancestry of “酸い”, step by step

Step	Language	Word	Meaning
1	Japanese	酢	vinegar
2	Middle Chinese	す	—

Words derived from “酸い”

Every word from Middle Chinese す →

酸い — Etymology, Origin & Word History | Etymology Explorer