Where does “chytrok” come from?

chytrok (Polish) comes from Polish Chytry, from Old Polish chytry, from Proto-Slavic xytrъ, from Proto-Slavic -rъ, from Proto-Indo-European -rós — Forms adjectives from Caland system roots.

Ancestry of “chytrok”, step by step

Step	Language	Word	Meaning
1	Polish	Chytry	sly, wily
2	Old Polish	chytry	cunning; insidious; deceptive
3	Proto-Slavic	xytrъ	cunning, sly, wise
4	Proto-Slavic	-rъ	From intransitive verbs or basic 0-grade stems,...
5	Proto-Indo-European	-rós	Forms adjectives from Caland system roots

Every word from Proto-Indo-European -rós →Every word from Proto-Slavic -rъ →Every word from Proto-Slavic xytrъ →