The Collaborative International Dictionary of English v.0.48:

Closet \Clos"et\, n. [OF. closet little inclosure, dim. of clos.
   See Close an inclosure.]
   1. A small room or apartment for retirement; a room for
      privacy.
      [1913 Webster]

            A chair-lumbered closet, just twelve feet by nine.
                                                  --Goldsmith.
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            When thou prayest, enter into thy closet. --Matt.
                                                  vi. 6.
      [1913 Webster]

   2. A small apartment, or recess in the side of a room, for
      household utensils, clothing, etc. --Dryden.
      [1913 Webster]

   Closet sin, sin commited in privacy. --Bp. Hall.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Closet \Clos"et\, v. t. [imp. & p. p.Closeted p. pr. & vb. n.
   Closeting.]
   1. To shut up in, or as in, a closet; to conceal. [R.]
      [1913 Webster]

            Bedlam's closeted and handcuffed charge. --Cowper.
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   2. To make into a closet for a secret interview.
      [1913 Webster]

            He was to call a new legislature, to closet its
            members.                              --Bancroft.
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            He had been closeted with De Quadra.  --Froude.
      [1913 Webster]

WordNet (r) 3.0 (2006):

closet
    n 1: a small room (or recess) or cabinet used for storage space
         [syn: cupboard, closet]
    2: a toilet in Britain [syn: water closet, closet, W.C.,
       loo]
    3: a tall piece of furniture that provides storage space for
       clothes; has a door and rails or hooks for hanging clothes
       [syn: wardrobe, closet, press]
    4: a small private room for study or prayer
    v 1: confine to a small space, as for intensive work

Moby Thesaurus II by Grady Ward, 1.0:

148 Moby Thesaurus words for "closet":
   WC, academic, adytum, anonymous, archives, armory, arsenal, attic,
   backhouse, bank, basement, bathroom, bay, bin, bonded warehouse,
   bookcase, booking office, bottle up, box, box in, box office,
   box up, branch, branch office, bunker, buttery, cabin, cabinet,
   can, cargo dock, casket, cellar, chambers, chancellery, chancery,
   chest, cloakroom, cloister, clothes closet, coffin,
   comfort station, confidential, confine, conservatory, consulate,
   convenience, corporate headquarters, cramp, crapper, crate, crib,
   cupboard, den, depository, depot, dock, drawer, dressing room,
   dump, earth closet, embassy, encase, entomb, exchequer,
   executive office, fitting room, glory hole, godown, head,
   headquarters, hold, holy of holies, home office, hushed, hutch,
   immure, incognito, inmost, innermost, inside, interior, intimate,
   inward, isolated, jakes, john, johnny, johnny house, latrine,
   lavatory, legation, library, linen closet, locker, lumber room,
   lumberyard, magasin, magazine, main office, necessary, office,
   outhouse, personal, powder room, private, privy, rack, repertory,
   repository, reservoir, rest room, retired, retreat, rick, sanctum,
   sanctum sanctorum, secluded, sequestered, shelf, shop, speculative,
   stack, stack room, stock room, storage, store, storehouse,
   storeroom, straiten, study, supply base, supply depot, tank,
   ticket office, toilet, toilet room, treasure house, treasure room,
   treasury, urinal, vat, vault, wardrobe, warehouse, washroom,
   water closet, wine cellar, withdrawn



Easton's 1897 Bible Dictionary:

Closet
   as used in the New Testament, signifies properly a storehouse
   (Luke 12: 24), and hence a place of privacy and retirement
   (Matt. 6:6; Luke 12:3).