Abuse refers to the use or treatment of something (a person, item, substance, concept, or vocabulary) that is harmful. It can be classed by the target of abuse or the type of abuse.

Classed by targets of abuse include:

• Animal abuse: Abuse or cruelty directed at animals.
• Child abuse: Abuse, usually physical, emotional or sexual, directed at a child.
• Elder abuse: Abuse, most often physical or in the form of psychological threats, directed at the elderly, especially in nursing homes and similar institutions.
• Spousal abuse (or domestic violence): Abuse, usually physical, or psychological abuse, directed at one's domestic partner.

Classed by type of abuse include

• Emotional abuse or psychological abuse: coercion, humiliation, intimidation, relational aggression, parental alienation or covert incest: Where one person uses emotional or psychological coercion to compel another to do something they do not want, or is not in their best interests; or when one person manipulates another's emotional or psychological state for their own ends (see battered person syndrome), or commits psychological aggression using ostensibly non-violent methods to inflict mental or emotional violence or pain on another.
• Physical abuse: Where one person inflicts physical violence or pain on another.
• Sexual abuse: The improper use of another person for sexual purposes, generally without their consent or under physical or psychological pressure (also, child sexual abuse, whether abused by parents, those in loco parentis or strangers).
• Spiritual abuse: abusive or aberrational practices identified in the behavior and teachings of some churches, spiritual and religious organizations and groups. These type of groups or organizations could be more accurately defined as a cult.
• Verbal abuse: When a person uses profanity, demeaning talk, or threatening statements.

It also includes abusing abstract concepts such as:

• Human rights abuse: Violation of human rights.
• Legal abuse: Vexatious litigation or malicious prosecution to retaliate, coerce, or emotionally/financially harm a person.

Other topics related to abuse include

• Drug abuse: the misuse of drugs, alcohol or other substances, usually a form of addiction. Law enforcement officials, among others, often define drug abuse as "any" use of illegal drugs, whether or not use is actually harmful to the user or to anyone else.
• Internet abuse includes a wide range of inappropriate online behavior, such as unsolicited promotional email, intrusion attempts, and phishing.