aggression

American  

[uh-gresh-uhn] / əˈgrɛʃ ən /

noun

1. the action of a state in violating by force the rights of another state, particularly its territorial rights; an unprovoked offensive, attack, invasion, or the like.

   The army is prepared to stop any foreign aggression.

   Antonyms:

   peacefulness

2. any offensive action, attack, or procedure; an inroad or encroachment.

   an aggression upon one's rights.

3. the practice of making assaults or attacks; offensive action in general.

4. Psychiatry. overt or suppressed hostility, either innate or resulting from continued frustration and directed outward or against oneself.

---

aggression British  

/ əˈɡrɛsə, əˈɡrɛʃən /

noun

1. an attack or harmful action, esp an unprovoked attack by one country against another

2. any offensive activity, practice, etc

   an aggression against personal liberty

3. psychol a hostile or destructive mental attitude or behaviour

---

aggression Scientific  

/ ə-grĕsh′ən /

1. Behavior that is meant to intimidate or injure an animal of the same species or of a competing species but is not predatory. Aggression may be displayed during mating rituals or to defend territory, as by the erection of fins by fish and feathers by birds.

---

Other Word Forms

• aggressor noun
• antiaggression adjective
• counteraggression noun
• preaggression noun

Etymology

Origin of aggression

1605–15; < Latin aggressiōn- (stem of aggressiō ), equivalent to aggress ( us ) ( aggress ) + -iōn- -ion

Explanation

Aggression is hostile, purposely unfriendly behavior that can sometimes be violent. A motorist who shows aggression for another may follow too closely, honk the horn, or otherwise try to intimidate. When someone deliberately tries to make another person feel intimidated or threatened, it's an act of aggression. Forceful, unfriendly behavior towards others is one example of aggression, and one country's hostile action toward another is also a kind of aggression. It's been used since the 1600s to mean "an unprovoked attack," from the Latin root word aggressionem, "attack," and in 1912 aggression was first used to mean generally "hostile behavior."

Example Sentences

"Given the usual tendencies of ants, I first assumed that I was observing aggression," Moffett said.

From Science Daily • Apr. 14, 2026

Incendiary is certainly a word one could use to describe public sentiment toward AI, which has barged into public life with a pace and aggression unlike any of its technological predecessors.

From Barron's • Apr. 14, 2026

Changes in the dominance hierarchy can fuel more aggression and tension, said Aaron Sandel, an associate professor of anthropology at the University of Texas at Austin and study co-author.

From The Wall Street Journal • Apr. 9, 2026

Not only do they thrive on aggression but their technical riffs and roaring anti-authoritarian sentiment seem to be more vital now than ever.

From Los Angeles Times • Apr. 9, 2026

Was it an emotion, like pride or aggression, or a type of illness?

From "Klawde: Evil Alien Warlord Cat" by Johnny Marciano and Emily Chenoweth

Related Words

• assault
• encroachment
• invasion
• offensive
• onslaught
• raid