Where does “купальник” come from?

купальник (Russian) comes from Russian -льник, from Ukrainian -ль, from Ukrainian -ь, from Proto-Slavic -ь, from Proto-Indo-European -is — Forms nouns from verbs.

купальник (Russian): swimsuit, bathing suit, swimwear

Definitions

swimsuit, bathing suit, swimwear

Ancestry of “купальник”, step by step

Step	Language	Word	Meaning
1	Russian	-льник	Suffix appended to nominal stems to create...
2	Ukrainian	-ль	Unproductive deverbal suffix used to form nouns denoting a product or a result
3	Ukrainian	-ь	—
4	Proto-Slavic	-ь	Forms nouns; From adjectives; From participles
5	Proto-Indo-European	-is	Forms nouns from verbs

Every word from Proto-Indo-European -is →Every word from Proto-Slavic -ь →Every word from Russian -льник →