Source : Webster's Revised Unabridged Dictionary (1913)

Ingratitude \In*grat"i*tude\, n. [F. ingratitude, L.
   ingratitudo. See {Ingrate}.]
   Want of gratitude; insensibility to, forgetfulness of, or ill
   return for, kindness or favors received; unthankfulness;
   ungratefulness.

         Ingratitude, thou marble-hearted fiend.  --Shak.

         Ingratitude is abhorred both by God and man.
                                                  --L'Estrange.

Source : WordNet®

ingratitude
     n : a lack of gratitude [syn: {ungratefulness}] [ant: {gratitude}]