The Collaborative International Dictionary of English v.0.48:

Monastic \Mo*nas"tic\, n.
   A monk.
   [1913 Webster] Monastic

The Collaborative International Dictionary of English v.0.48:

Monastic \Mo*nas"tic\, Monastical \Mo*nas"tic*al\, a. [Gr. ?
   monk: cf. F. monastique. See Monastery.]
   1. Of or pertaining to monasteries, or to their occupants,
      rules, etc., as, monastic institutions or rules.
      [1913 Webster]

   2. Secluded from temporal concerns and devoted to religion;
      recluse. "A life monastic." --Denham.
      [1913 Webster]

WordNet (r) 3.0 (2006):

monastic
    adj 1: of communal life sequestered from the world under
           religious vows [syn: cloistered, cloistral,
           conventual, monastic, monastical]
    n 1: a male religious living in a cloister and devoting himself
         to contemplation and prayer and work [syn: monk,
         monastic]

Moby Thesaurus II by Grady Ward, 1.0:

41 Moby Thesaurus words for "monastic":
   abbacomes, abbot, ascetic, beadsman, brother, caloyer, celibataire,
   celibate, cenobite, claustral, cloistered, conventical, conventual,
   conventual prior, friar, grand prior, hermit, hieromonach,
   lay abbot, lay brother, mendicant, misogamic, misogamist,
   misogynist, misogynous, monachal, monasterial, monk, monkish, nun,
   palmer, pilgrim, pillar saint, pillarist, priest, prior, religieux,
   religious, single, stylite, unmarried