The Collaborative International Dictionary of English v.0.48:

Erroneous \Er*ro"ne*ous\, a. [L. erroneus, fr. errare to err.
   See Err.]
   1. Wandering; straying; deviating from the right course; --
      hence, irregular; unnatural. [Obs.] "Erroneous
      circulation." --Arbuthnot.
      [1913 Webster]

            Stopped much of the erroneous light, which otherwise
            would have disturbed the vision.      --Sir I.
                                                  Newman.
      [1913 Webster]

   2. Misleading; misled; mistaking. [Obs.]
      [1913 Webster]

            An erroneous conscience commands us to do what we
            ought to omit.                        --Jer. Taylor.
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   3. Containing error; not conformed to truth or justice;
      incorrect; false; mistaken; as, an erroneous doctrine;
      erroneous opinion, observation, deduction, view, etc. --
      Er*ro"ne*ous*ly, adv. -- Er*ro"ne*ous*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

erroneous
    adj 1: containing or characterized by error; "erroneous
           conclusions"