noun; clipping of "aggression"
In videogames, to draw the attention and subsequent attacks of a previously neutral AI.
Don't pass by the goblins, you'll draw their aggro.
Etymology : Aggression "unprovoked attack" from French aggression, from Latin aggressionem "a going to, an attack", noun of aggredi "to approach, attack", from ad- "to" + gradi "to step". Aggro is an altered clipping of aggression. The "aggr" is clearly from "aggression", but the ending "-o" doesn't occur in the original word. Likely the ending formed from the clipping "aggre", and the ending middle vowel subsequently became the back vowel.
Source : Dota 2, February 2013
Last modified: 25 November 2013