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]WordNet (r) 3.0 (2006):
cloistral adj 1: of communal life sequestered from the world under religious vows [syn: cloistered, cloistral, conventual, monastic, monastical]