aggression

UK: /əˈgrɛʃ^ən/ US: /əˈgrɛʃən/ ,(ə gresh′ən)

WordReference Random House Learner's Dictionary of American English © 2026

ag•gres•sion /əˈgrɛʃən/   n. [uncountable]

1. the action of making unprovoked assaults or attacks against another, esp. so as to dominate.
2. Psychology hostility toward or attack upon another, whether in words or in gestures or other acts:
   The panhandler's aggression frightened the passersby.

ag•gres•sor /əˈgrɛsɚ/  n. [countable] See -gress-.

WordReference Random House Unabridged Dictionary of American English © 2026

ag•gres•sion  (ə gresh′ən), n. 

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.
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.

• Latin aggressiōn- (stem of aggressiō), equivalent. to aggress(us) (see aggress) + -iōn- -ion
• 1605–15

Antonyms

• 1. peacefulness.

Collins Concise English Dictionary © HarperCollins Publishers::

aggression / əˈɡrɛʃən/ noun

1. an attack or harmful action, esp an unprovoked attack by one country against another
2. any offensive activity, practice, etc
3. a hostile or destructive mental attitude or behaviour

Etymology: 17th Century: from Latin aggression-, from aggrēdi to attack

aggressor / əˈɡrɛsə/ noun