Source : Webster's Revised Unabridged Dictionary (1913)

Disingenuous \Dis`in*gen"u*ous\, a.
   1. Not noble; unbecoming true honor or dignity; mean;
      unworthy; as, disingenuous conduct or schemes.

   2. Not ingenuous; wanting in noble candor or frankness; not
      frank or open; uncandid; unworthily or meanly artful.

            So disingenuous as not to confess them [faults].
                                                  --Pope.
      -- {Dis`in*gen"u*ous*ly}, adv. --T. Warton. --
      {Dis`in*gen"u*ous*ness}, n. --Macaulay.

Source : WordNet®

disingenuous
     adj : not straightforward or candid; giving a false appearance of
           frankness; "an ambitious, disingenuous, philistine, and
           hypocritical operator, who...exemplified...the most
           disagreeable traits of his time"- David Cannadine; "a
           disingenuous excuse" [syn: {artful}] [ant: {ingenuous}]