bitterness

(noun) a feeling of deep and bitter anger and ill-will. Synonyms: resentment, gall, rancor, rancour.

(noun) a rough and bitter manner. Synonyms: acrimony, acerbity, jaundice, tartness, thorniness.

(noun) the taste experience when quinine or coffee is taken into the mouth. Synonyms: bitter.

(noun) the property of having a harsh unpleasant taste. Synonyms: bitter.