A British term, given to someone who says something stupid or makes a stupid remark, usually due to living a sheltered life and having little exposure or knowledge about the world around them.
J: “Want some halloumi for dinner?”
L: “The city in Hawaii?”
J: “No, the cheese! You’re such a pollywoppus!”
When the something, someone, you are pointing out is directionally diagonal across an intersection from you. Not accross either street from you but diaganol across both streets. See Kitty Corner.
The bank is pollywompus from the market at the corner of Broadway and 4th Ave.