Collins COBUILD Advanced Learner's English Dictionary - maniacal

If you describe someone’s behaviour as maniacal, you mean that it is extreme, violent, or very determined, as if the person were insane. He was almost maniacal in his pursuit of sporting records... She is hunched forward over the wheel with a maniacal expression. ADJ c darkgreen]disapproval • maniacally He was last seen striding maniacally to the hotel reception. ADV: usu ADV with v, also ADV adj