The Collaborative International Dictionary of English v.0.48:

Cloisteral \Clois"ter*al\, a.
   Cloistral. [Obs.] --I. Walton.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cloistral \Clois"tral\, a.
   Of, pertaining to, or confined in, a cloister; recluse.
   [Written also cloisteral.]
   [1913 Webster]

         Best become a cloistral exercise.        --Daniel.
   [1913 Webster]