1. a person who treats someone or something with cruelty or violence
2. a person who uses something in a harmful or improper way

Examples

• The child was removed from the home due to concerns about the abuser.
• Domestic violence shelters provide safety for victims and their children from abusers.
• The drug abuser sought help at a rehabilitation center.
• Animal rights activists protested against known animal abusers.
• The system abuser exploited loopholes for personal gain.
• Counseling programs help both victims and abusers break cycles of violence.
• The substance abuser’s family staged an intervention.