From Longman Dictionary of Contemporary Englishidiocyid‧i‧o‧cy /ˈɪdiəsi/ noun (plural idiocies)[countable, uncountable]STUPID/NOT SENSIBLE something that you think is extremely silly or stupidSYN stupidityThe idiocy of his behaviour appalled her.He smiled calmly at the idiocies of mankind.Examples from the Corpusidiocy• But she stayed on this balcony, her eyes on him, on this shape which fear had reduced to animal idiocy.• As a prominent figure in Rottweilerrescue, she's stubbed her toe on more unfairbullying and downright idiocy than most.• Learning a languagemeans returning to a state of near idiocy.• There was only one way to knock such idiocy in the head.• That idiocy about H. G. Wells.• It stung, that eruption of uncomprehendingidiocy.