a person, group, or nation that attacks first or initiates hostilities; an assailant or invader.

Origin of aggressor

1670–80; < Late Latin, Latin aggred- (stem of aggredī to attack; see aggress) + -tor -tor Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for aggressor

Contemporary Examples of aggressor

Historical Examples of aggressor

Word Origin and History for aggressor

1670s, from Latin aggressor, agent noun from aggredi (see aggression).

Online Etymology Dictionary, © 2010 Douglas Harper