The Collaborative International Dictionary of English v.0.48:

Introvert \In`tro*vert"\, v. t. [imp. & p. p. Introverted; p.
   pr. & vb. n. Introverting.] [Pref. intro- + L. vertere,
   versum, to turn.]
   [1913 Webster]
   1. To turn or bend inward. "Introverted toes." --Cowper.
      [1913 Webster]

   2. To look within; to introspect. --Lew Wallace.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

introverted \in"tro*vert`ed\ adj.
   1. examining one's own sensory and perceptual experiences.
      Contrasted with extrospective.

   Syn: introspective.
        [WordNet 1.5]

   2. marked by concern predominantly with oneself or one's own
      feelings. Contrasted with extroverted.

   Syn: introvert, introvertive.
        [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

introverted
    adj 1: given to examining own sensory and perceptual experiences
           [syn: introspective, introverted, self-examining]
           [ant: extrospective, extroverted]

Moby Thesaurus II by Grady Ward, 1.0:

69 Moby Thesaurus words for "introverted":
   Olympian, aloof, arsy-varsy, ass over elbows, back-to-front,
   backward, backwards, bashful, blank, capsized, chiastic, chilled,
   chilly, cold, constrained, cool, detached, discreet, distant,
   everted, expressionless, forbidding, frigid, frosty, guarded,
   hyperbatic, icy, impassive, impersonal, inaccessible, ingoing,
   inner-directed, inside out, introversive, introvert, invaginated,
   inversed, inverted, modest, offish, outside in, palindromic,
   remote, removed, repressed, reserved, restrained, resupinate,
   reticent, retiring, retroverted, reversed, shrinking, standoff,
   standoffish, subdued, subjective, suppressed, topsy-turvy,
   transposed, unaffable, unapproachable, uncongenial,
   undemonstrative, unexpansive, ungenial, upside-down, withdrawn,
   wrong side out