Where does “Pliś” come from?

Pliś (Polish) comes from Polish pliszka, from Old Polish pliska, from Proto-Slavic *pliska.

Ancestry of “Pliś”, step by step

Step	Language	Word	Meaning
1	Polish	pliszka	wagtail
2	Old Polish	pliska	—
3	Proto-Slavic	*pliska	—

Pliś — Etymology, Origin & Word History | Etymology Explorer