There also is a French form, Léonise (
https://www.behindthename.com/name/le10onise/submitted).
According to a French website, Léonise means "bold in battle"; however, this seems unlikely, as I couldn't find any similar name elements.
So this is most likely a feminine form of Leon or its forms, since there are a lot of them (Leona, Leoncia, Leonarda, Léonide, Leonia, Leontina, Léonine...).
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