Stunned

From NWNWiki

Stunned creatures stand helplessly in a motionless stupor and are considered prone flat-footed.

Creatures attacking them receive a +2 bonus to their attack roll. After every flurry any prone condition is removed from the stunned creature (For example if a stun creature is knocked down, then each blow thereafter during that flurry will receive both the prone bonus/penalty and the stunned bonus, while attacks after that flurry will receive only the stunned bonus). The effects of stun, including the +2 bonus to attackers and its ability to interfere with the prone condition, are overridden by paralysis, sleep, and petrification.