The Collaborative International Dictionary of English v.0.48:

Restrict \Re*strict"\, v. t. [imp. & p. p. Restricted; p. pr.
   & vb. n. Restricting.]
   To restrain within bounds; to limit; to confine; as, to
   restrict worlds to a particular meaning; to restrict a
   patient to a certain diet.
   [1913 Webster]

   Syn: To limit; bound; circumscribe; restrain; repress; curb;
        coerce.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

classified \classified\ adj.
   1. arranged into classes or categories; as, unclassified.

   Syn: categorized.
        [WordNet 1.5 +PJC]

   2. assigned to a class of documents withheld from general
      circulation; -- of information or documents. Opposite of
      unclassified.

   Note: [Narrower terms: eyes-only; confidential;
         restricted; secret; sensitive; top-secret]
         [WordNet 1.5]

WordNet (r) 3.0 (2006):

restricted
    adj 1: subject to restriction or subjected to restriction; "of
           restricted importance" [ant: unrestricted]
    2: restricted in meaning; (as e.g. `man' in `a tall man') [syn:
       restricted, qualified]
    3: the lowest level of official classification for documents

Moby Thesaurus II by Grady Ward, 1.0:

117 Moby Thesaurus words for "restricted":
   angustifoliate, angustirostrate, angustisellate, angustiseptal,
   arcane, authoritative, bound, bounded, boxed in, cabalistic,
   cabined, censored, circumscribed, classified, cloistered, close,
   close-fitting, closed, concealed, conditioned, confined,
   constricted, copyrighted, cramp, cramped, cribbed, crowded,
   cryptic, dark, detained, determinate, disciplined, enclosed,
   enigmatic, esoteric, expert, feature, featured, finite, fixed,
   hedged, hedged about, hedged in, hemmed in, hermetic, hidden,
   hush-hush, icebound, impounded, in confinement, incapacious,
   incommodious, isthmian, isthmic, kept in, knowledgeable,
   landlocked, latent, leavened, limited, meager, mitigated,
   moderated, modified, modulated, mysterious, narrow, near, occult,
   off limits, out of bounds, patented, pent, pent-up, precise,
   prescribed, proscribed, qualified, scant, scanty, seasoned, secret,
   shut-in, slender, smothered, snowbound, softened, specialist,
   specialistic, specialized, stifled, stinted, strait, straitened,
   suppressed, technical, tempered, tight, top secret, ulterior,
   unbreatheable, under restraint, under security, under wraps,
   undisclosable, undisclosed, undivulgable, undivulged, unrevealable,
   unrevealed, unspoken, untellable, untold, unutterable, unuttered,
   unwhisperable, windbound