bitterness in WordNet English dictionary

1. a rough and bitter manner
   bitterness  acrimony  acerbity  jaundice  tartness  thorniness 
   
2. the property of having a harsh unpleasant taste
   bitterness  bitter 
   
3. the taste experience when quinine or coffee is taken into the mouth
   bitter  bitterness 
   
4. a feeling of deep and bitter anger and ill-will
   resentment  bitterness  gall  rancor  rancour