Source : Webster's Revised Unabridged Dictionary (1913)

Substantial \Sub*stan"tial\, a. [F. substantiel, L.
   substantialis.]
   1. Belonging to substance; actually existing; real; as,
      substantial life. --Milton.

            If this atheist would have his chance to be real and
            substantial agent, he is more stupid than the
            vulgar.                               --Bentley.

   2. Not seeming or imaginary; not illusive; real; solid; true;
      veritable.

            If happinessbe a substantial good.    --Denham.

            The substantial ornaments of virtue.  --L'Estrange.

   3. Corporeal; material; firm. ``Most ponderous and
      substantial things.'' --Shak.

            The rainbow [appears to be] a large substantial
            arch.                                 --I. Watts.

   4. Having good substance; strong; stout; solid; firm; as,
      substantial cloth; a substantial fence or wall.

   5. Possessed of goods or an estate; moderately wealthy;
      responsible; as, a substantial freeholder. ``Substantial
      yeomen and burghers.'' --Sir W. Scott.

Source : WordNet®

substantial
     adj 1: fairly large; "won by a substantial margin" [syn: {significant}]
     2: being the essence or essential element of a thing;
        "substantial equivalents"; "substantive information" [syn:
         {substantive}, {in essence}]
     3: having substance or capable of being treated as fact; not
        imaginary; "the substantial world"; "a mere dream, neither
        substantial nor practical"; "most ponderous and
        substantial things"- Shakespeare [syn: {real}, {material}]
        [ant: {insubstantial}]
     4: providing abundant nourishment; "a hearty meal"; "good solid
        food"; "ate a substantial breakfast" [syn: {hearty}, {satisfying},
         {solid}]
     5: of good quality and condition; solidly built; "a solid
        foundation"; "several substantial timber buildings" [syn:
        {solid}, {strong}]