vitriolic

• Meaning: bitterly scathing / harsh / abusive (in criticism, in expression, in feeling)
  
• note: vitriol = sulfuric acid
  
• In Hong Kong slang: 狂插
  
• In decent Chinese: 尖酸， 刻薄
  
• Where we first met: BBC News on the salary dispute between university lecturers' union and their employers - ' ... often descends into vitriolic disagreement over what is, or is not, a "fact".'