Where does “kärkeväsanainen” come from?

kärkeväsanainen (Finnish) comes from Finnish sanainen, from Finnish sana, from Finnish luokka, from Finnish luokki, from Proto-Slavic lǫkъ, from Proto-Balto-Slavic *lankás, from Proto-Indo-European lenk- — to bend.

Ancestry of “kärkeväsanainen”, step by step

kärkeväsanainen traces back through two separate lines of ancestry.

via Finnish sanainen

Step	Language	Word	Meaning
1	Finnish	sanainen	worded; verbal
2	Finnish	sana	word; Word, Scripture; lesson
3	Finnish	luokka	class; class, social class; grade
4	Finnish	luokki	shaft bow
5	Proto-Slavic	lǫkъ	bow
6	Proto-Balto-Slavic	*lankás	bow
7	Proto-Indo-European	lenk-	to bend

via Finnish kärkevä

Step	Language	Word	Meaning
1	Finnish	kärkevä	sharp-tempered, acerbic, poignant, polemic, sharp
2	Finnish	kärki	point, tip, cusp; lead; vertex
3	Proto-Finnic	kärki	black woodpecker
4	Proto-Finno-Permic	kärke	—

Every word from Proto-Indo-European lenk- →Every word from Proto-Balto-Slavic *lankás →Every word from Proto-Slavic lǫkъ →