Synonyms: abuse, misuse, mistreat, ill-treat, maltreat

These verbs mean to treat wrongfully or harmfully. 

• Abuse applies to injurious or improper treatment:
      "We abuse land because we regard it as a commodity belonging to us" Aldo Leopold.
  
  
• Misuse stresses incorrect or unknowledgeable handling:
      "How often misused words generate misleading thoughts" Herbert Spencer.
  
  
• Mistreat, ill-treat, and maltreat all share the sense of inflicting injury, often intentionally:
      "I had seen many more patients die from being mistreated for consumption than from consumption itself" Earl of Lytton.
      The army had orders not to ill-treat the prisoners.
     "When we misuse [a language other than our native language], we are in fact trying to reduce its element of foreignness. We let ourselves maltreat it as though it naturally belonged to us" Manchester Guardian Weekly.

... The American Heritage® Dictionary of the English Language