The four As
Anger is an emotion, the feel of an experience, a state of mind. It is neither good nor bad, but usually has negative effects on the person feeling it, and is associated with the colour red (love with pink, jealousy with green). It can be expressed safely to others using an I-statement: “I am angry that you said that”.
As long as the separateness of another person is respected, as long as anger is expressed TO and not AT another person, anger can be shared without hurting someone else.
Aggression is anger expressed AT another person. Aggression hurts others. Overt aggression is conveyed in ways that are usually obvious, whether verbally or physically, as jabs or punches. Covertly it is usually expressed by acts of omission, silence or other forms of passive aggression. Though aggression may hurt others, it is not necessarily aimed at or intended to hurt anyone.
Attacks are aimed at another person with the intention of causing harm. Attacks consist in words or actions directed at someone, a target, for the express purpose of hurting him or her. The motivation may be anger, but more often the motivation is revenge, which can and often does occur in the absence of anger; in fact, the fire of emotion is usually absent from premeditated or terrorist attacks, which is why they are cold-blooded, the most insidious attacks of all.
Abuse is a pattern of aggression which harms, frightens or controls another person. It is situation-specific. Context, like power differentials and the effects on the victim, need to be considered in order to determine whether it is abuse. For example, a woman may hit a man but the man may not feel frightened; whereas a woman almost always feels frightened when a man hits her. A child may scream at his mother but the mother may not feel controlled; whereas a child almost always feels terrorized by a screaming mother. A student may sleep with her teacher but the teacher is usually not harmed; whereas the student almost always is.
Abuse, unlike an attack, may not be intended, and it usually isn’t. Nevertheless, it is still harmful and it is still abuse.