This is a noun that describes a person who is not only dumb, but also rude in their actions. It is a combination of dumbass and asshole used to save time after explanation a frustrating event.
A person who goes above and beyond normal stupidity by being rude about it. Also someone who is incorrect or wrong so blatantly and yet refuses to give in to reason and or the facts.
The dumbasshole insisted that he could defuse the bomb even though he was never trained to disarm explosives.
The dumbasshole mispelled the word and refused to believe their mistake even after I showed them the correct spelling in the dictionary