Where does “krank” come from?

krank (Old Dutch) comes from Proto-Germanic krankaz, from Proto-Indo-European ger- — to turn, bend, twist, wind; to tie, bind...

Ancestry of “krank”, step by step

Step	Language	Word	Meaning
1	Proto-Germanic	krankaz	bent; crooked; weak
2	Proto-Indo-European	ger-	to turn, bend, twist, wind; to tie, bind...