Source : Webster's Revised Unabridged Dictionary (1913)

Enormous \E*nor"mous\, a. [L. enormis enormous, out of rule; e
   out + norma rule: cf. F. ['e]norme. See {Normal}.]
   1. Exceeding the usual rule, norm, or measure; out of due
      proportion; inordinate; abnormal. ``Enormous bliss.''
      --Milton. ``This enormous state.'' --Shak. ``The hoop's
      enormous size.'' --Jenyns.

            Wallowing unwieldy, enormous in their gait.
                                                  --Milton.

   2. Exceedingly wicked; outrageous; atrocious; monstrous; as,
      an enormous crime.

            That detestable profession of a life so enormous.
                                                  --Bale.

   Syn: Huge; vast; immoderate; immense; excessive; prodigious;
        monstrous.

   Usage: -- {Enormous}, {Immense}, {Excessive}. We speak of a
          thing as enormous when it overpasses its ordinary law
          of existence or far exceeds its proper average or
          standard, and becomes -- so to speak -- abnormal in
          its magnitude, degree, etc.; as, a man of enormous
          strength; a deed of enormous wickedness. Immense
          expresses somewhat indefinitely an immeasurable
          quantity or extent. Excessive is applied to what is
          beyond a just measure or amount, and is always used in
          an evil; as, enormous size; an enormous crime; an
          immense expenditure; the expanse of ocean is immense.
          ``Excessive levity and indulgence are ultimately
          excessive rigor.'' --V. Knox. ``Complaisance becomes
          servitude when it is excessive.'' --La Rochefoucauld
          (Trans).

Source : WordNet®

enormous
     adj : extraordinarily large in size or extent or amount or power
           or degree; "an enormous boulder"; "enormous expenses";
           "tremendous sweeping plains"; "a tremendous fact in
           human experience; that a whole civilization should be
           dependent on technology"- Walter Lippman; "a plane took
           off with a tremendous noise" [syn: {tremendous}]