1- It's used for
dumb people but in a higher meaning
2- It's used instead of saying: you're a shit
dumb
3- Used for people when they say something stupid or something boring
Matthew: you see that man, i don't
fucking like him, he's
dumb!
Patrick: yeah! we've been in touch, and he's a dump!
Victor: i've almost finished my project, and you screw it up ! you dump!