One belonging to, or living in, a cloister; a recluse.
friar
noun
An American fish, the silverside.
A member of a mendicant Christian order such as the Augustinians, Carmelites (white friars), Franciscans (grey friars) or the Dominicans (black friars).
How often have the words cloisterer and friar occurred in a corpus of books? (source: Google Ngram Viewer )