Laggro is the act of acquiring the aggro of an enemy Non Player Character in an MMO at the same time that your computer is loading the content. Laggro generally happens with an older computer that isn't quite up to par for the game being played but can also be a result of a high density of players in a localized area. Mild laggro is a nuisance, extreme laggro usually results in a free run back from the rez circle.
When I went into the new instance, I caught some serious laggro and died before my computer even finished loading.
by Blackhelm February 21, 2008