(Reply is not working on mobile. This is to Aaron.) It is not plural. Plural is "women's sweaters" (with the extra "s"). Think of it this way: you could write "a women's sweater" as "a sweater for women".
Why is the English translation of светр "jumper"? Shouldn't it be "sweater".
It's British, I found out. In American, a jumper is jumpsuit or a "one-sie." A светр is just a sweater
A woman ( singular) / women ( plural) So : a woman’s sweater Women’s sweaters