מְנַשִּׁי Mᵉnashshîy (H4520)

a Menashshite or descendant of Menashsheh

Manassites = Manasseh "causing to forget" 1) descendants of Manasseh, son of Joseph and grandson of Jacob 1a) specifically used only of that half that lived east of the Jordan

from מְנַשֶּׁה (H4519);