\Im*bit"ter\, v. t. [imp. & p. p. {Imbittered}; p. pr.
& vb. n. {Imbittering}.] [Pref. im- in + bitter. Cf.
{Embitter}.] [Written also {embitter}.]
To make bitter; hence, to make distressing or more
distressing; to make sad, morose, sour, or malignant.

      Is there anything that more imbitters the enjoyment of
      this life than shame?                    --South.

      Imbittered against each other by former contests.
                                               --Bancroft.