Source : Webster's Revised Unabridged Dictionary (1913)

Chimerical \Chi*mer"ic*al\, a.
   Merely imaginary; fanciful; fantastic; wildly or vainly
   conceived; having, or capable of having, no existence except
   in thought; as, chimerical projects.

   Syn: Imaginary; fanciful; fantastic; wild; unfounded; vain;
        deceitful; delusive.

Source : WordNet®

chimerical
     adj 1: being or relating to or like a chimera; "his Utopia is not
            as chimeric commonwealth but a practical improvement
            on what already exists"- Doublas Bush [syn: {chimeric},
             {chimeral}]
     2: produced by a wildly fanciful imagination; "his Utopia is
        not a chimerical commonwealth but a practical improvement
        on what already exists"- Douglas Bush