Berserk
Part of speech: noun
Definition: A crazed Norse warrior who fought in a frenzy.
Part of speech: adjective
Definition: Injuriously, maniacally, or furiously violent or out of control.
Berserker
Part of speech: noun
Definition: One of a class of legendary Norse warriors who fought frenzied and shirtless regardless of wounds (possibly due to ingestion of psychotropic and hallucinatory drugs such as Fly Agaric Mushrooms).One who fights as if frenzied, like a Berserker.