Source : Webster's Revised Unabridged Dictionary (1913)

Ingrateful \In"grate`ful\, a. [L. ingratus ingrateful (pref. in-
   not + gratus beloved, dear, grateful) + -ful: cf. F. ingrat.
   See {Grateful}.]
   1. Ungrateful; thankless; unappreciative. --Milton.

            He proved extremely false and ingrateful to me.
                                                  --Atterbury.

   2. Unpleasing to the sense; distasteful; offensive.

            He gives . . . no ingrateful food.    --Milton.
      -- {In"grate`ful*ly}, adv. -- {In"grate`ful*ness}, n.