/ əˈgreʃn; NAmE / noun [ U ]
1.
feelings of anger and hatred that may result in threatening or violent behaviour :
The research shows that computer games may cause aggression.
2.
a violent attack or threats by one person against another person or by one country against another country :
unprovoked military aggression
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WORD ORIGIN
early 17th cent. (in the sense an attack ): from Latin aggressio(n-) , from aggredi to attack, from ad- towards + gradi proceed, walk.