northern english slang term. a mardybum is someone who is sulking or pouting for attention, due to something small or insignificant happening that causes minimum inconvenience. usually used as something to aggrovate a child into being more happy, a simple form of reverse psychology. recently immortalised in the seminal classic "mardybum" by the artic monkeys.
mother: (to child) what do you want for dinner?
**child fails to respond**
mother: ooohhh, you mardybum!
now then, mardybum! - arctic monkeys