ambiversion

from WordNet (r) 3.0 (2006)

ambiversion
    n 1: (psychology) a balanced disposition intermediate between
         extroversion and introversion [ant: {extraversion},
         {extroversion}, {introversion}]

from The Collaborative International Dictionary of English v.0.48

ambiversion \ambiversion\ n.
   1. a balanced disposition intermediate between extroversion
      and introversion.
      [WordNet 1.5]

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