Definition of: aggression

(ə·gresh′ən) noun
1. An unprovoked attack; encroachment.
2. Habitual aggressive action or practices.
3. Psychoanal. A primary instinct, generally associated with emotional states, to carry out action in a forceful way. Synonyms: assault, attack, encroachment, incursion, intrusion, invasion, onslaught, trespass. An attack may be by word; an aggression is always by deed. An assault may be upon the person, an aggression is upon rights, possessions, etc. An invasion of a nation's territories is an act of aggression; an intrusion upon a neighboring estate is a trespass. On-slaught signifies intensely violent assault, as by an army or a desperado, yet it is some times used of violent speech. Antonyms: defense, repulsion, resistance, retreat.