Some one who can'tthink for them selves or otherwise thought as stupid.
Will robertson is a dumbass for thinking he's not hipster. When someone turns into a zombie why do they turn into a dumbass? "Why are Brad and Angelina together? I think their a bunch of dumbasses"
a randomkid you meet online in a video game, usually halo, call of duty, battlefield, or gears of war. they think they are the best players ever, but actually suck.
This kid just picked up the boomshot and killed himself, what a dumbassrandom.
When an individual is so exhausted that their cognitive skills are compromised, effectively lowering their IQ
Jules was so fatigued after the long hours of driving that she could not remember whether to put out the recycling, the garbage, or the cat. Swaying with exhaustion she exclaimed, "I put the milk in the closet and the detergent in the fridge just now. I am officially dumbass tired!"