Where does “klār” come from?

klār (Middle Low German) comes from Latin clārus, from Proto-Indo-European ḱelh₁- — to warm up, to be hot; to warm up, be hot.

Ancestry of “klār”, step by step

Step	Language	Word	Meaning
1	Latin	clārus	—
2	Proto-Indo-European	ḱelh₁-	to warm up, to be hot; to warm up, be hot

klār — Etymology, Origin & Word History | Etymology Explorer