D'mah
A fancy way of saying 'dumbass' that only smart people use to hide their own dumbness. It's like pretending you're not the one who made the mistake.
She said, 'D'mah, he just yelled at the calculator.'
He said, 'D'mah, he tried to ride a bicycle with his hands.'
He mouthed, 'D'mah, he said the sun was a giant lightbulb.'