【Abuse】 , 【misuse】 , 【mistreat】 , 【maltreat】 , 【ill-treat】 and 【outrage】 all denote to use or treat a person or thing improperly or wrongfully.

【Abuse】 and 【misuse】 are capable of wider use than the others, for they do not invariably imply either deliberateness or wantonness.

• I can't 【abuse】 your generosity to that extent. You're doing more than enough for me already.
  —Mackenzie
• It turns a man's stomach to hear the Scripture misused in that way.
  —George Eliot

【Abuse】 , however, commonly suggests perversion of the ends for which something was intended.

• The constitution leaves them [the states] this right in the confidence that they will not 【abuse】 it.
  —John Marshall

Sometimes it implies excess in use that injures or impairs.

• 【abuse】 one's strength

【Misuse】 , by contrast with 【abuse】 , emphasizes the actual mistreatment or misapplication rather than its results.

• The intent of this regulation is highly commendable, namely to keep the Indians from being misused.
  —Hitchcock

【Mistreat】 , 【maltreat】 , and illtreat usually imply a fault or an evil motive in the agent, such as meanness, culpable ignorance, or spitefulness.

• Many more patients die from being mistreated for consumption than from consumption itself.
  — Lytton
• The meter, though a well-known English critic has maltreated it of late, is a very fine one.
  —Saintsbury
• have small compunction in ill-treating animals, because they have no souls
  —Repplier

【Outrage】 implies 【abuse】 so violent or extreme as to exceed all bounds.

• an act that outraged nature and produced the inevitable tragedy of the play
  — Auchincloss