Source : Webster's Revised Unabridged Dictionary (1913)

Cloister \Clois"ter\, v. t. [imp. & p. p. {Cloistered}; p. pr. &
   vb. n. {Cloistering}.]
   To confine in, or as in, a cloister; to seclude from the
   world; to immure.

         None among them are thought worthy to be styled
         religious persons but those that cloister themselves up
         in a monastery.                          --Sharp.