Short for aggressive or aggression. Can be used to describe how a person is behaving. Also in MMORPGs such as World of Warcraft it refers to an enemy attacking you if you get too close to it. In MMORPGs certain enemies have different ranges that will trigger them to attack. Some enemies can attack even when you are fairly far away and some only attack when your characters is right next to the enemy or in very close proximity. Higher level enemies tend to have a larger range than lower level ones.
"Chill out, what is with the aggro today?"

"That idiot in our group just pulled aggro on a group of elite murlocs!"

"You're pulling fucking aggro from them! Run for it!"
by IceWarm January 25, 2006
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Noun: Aggro/agro
Verb: Aggroing
Adjective: Aggroed

A term used by many gamers referring to tipping off any NPC or animal, and causing it to want to fight you.
Example from Ark: Survival Evolved

Holy crap I just aggroed the Tickle Chicken!!! Run!!
by Gamer4200 December 19, 2019
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An shortened version of the term "aggravated". You hear it often used in MMORPG's as a way of telling others who the mobs are attacking. In most MMORPG's it is the duty of the Tank to keep "aggro" (having all the mobs attacking him only) so the DPS players don't have to worry about dying and the Healers don't have to worry about healing the DPS players or using AOE healing moves.
Sirkillsalot (DPS): Hey amazing, I just pulled aggro on the goblin.
Iamamazing445 (Tank): I'll come get him.
SparklezznHealzz (Healer): I don't have enough mana to heal both of you.
Sirkillsalot (DPS): I'll come to middle, just use an AOE.
SparklezznHealzz (Healer): Ugh, okay. Amazing, I need you to keep your aggro, my AOE's are weak.
Iamamazing445 (Tank): Yeah, yeah, got it sparklezz.
RandySavage001 (Tank): Guys, you're doing too much DPS, I'm having a hard time keeping aggro on the Witch Lord.
Death2BabySeals (DPS): I can help dual-tank to keep aggro off of DPS.
Biblebasher1 (Healer): Yeah, then I can focus on AOE heals, so even if you do lose aggro DPS should be safe.
Death2BabySeals (Tank): Pulling aggro now.
by Rusel Crow December 2, 2013
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Having the attention of someone/something.

Often used term in the game "World of Warcraft".
Casters, if you pull aggro you need to dump it.

Wait for the tank to aggro.

Be careful that you don't pull aggro.

Hunter pulls, tank aggros, kill the marked.
by MePoop April 20, 2006
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usually meaning Industrial Metal, but also could mean agressive
by Edwin December 27, 2003
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In an MMORPG when you "piss off" an NPC(non-player character) and it enters a combat state with your character. Most often used when multiple NPC's are attacking you because you got too close or you attacked them.
"I just aggro'd 15 level 80's! I need a heal!"
by lowell August 9, 2005
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