When you seclude someone, you separate them from other people. A Buddhist monk might seclude himself in a remote place to meditate alone for several weeks.
Most people use the verb seclude to talk about shutting themselves away from society or keeping themselves separate from others. An eccentric family might seclude itself from the neighbors, for example. The root is Latin, secludere, which means "shut off or confine," from se, "apart" and cludere, "to shut." Originally, seclude was used to mean "to enclose or confine," and by the 1620s it also meant "to keep from public view."