Another word for stupid, object of calling someone this is to make them feel less than the person who's calling them "Stupad" Or "Stupid". Miss spelt on purpose making calling someone "Stupad"/"Stupid" Ironic.
adj. - Something stupefying, generally used in a positive fashion. Used to denote a level of something so enormous, it's ridiculous almost to the point of being stupid.
Also used as an adv., it is less ubiquitously positive when found in this form.
You check that cat on the sax? He's so good it's stupidacious!