昏
コン, くら.い, くれ

dark, evening, dusk

JLPT0 G13 S0 F5000

The relevant bronzeware inscription form shows the character was originally 昬, which is 民# (blind) + 日 sun/day → dark night/*darkness* in which nothing can be seen → *evening*; *sunset*; *nightfall* → *blind*; *blindness*.

[Full Kanji Etymology List]