Formally, a caped gweirdo is a complex mythical term but can be used as an insult. In its more common usage, it specifically implies that someone is beyond weird, physically aggressive, and dresses themselves in strange attire to intimidate. The term can also just mean mean or aggressive over small things. The plural is caped gweirdoz not caped gweirdos.
"He is such a caped gweirdo!"
by dr.gweirdo December 5, 2019