IPA: /ˈɪdiəsi/
KK: /ˈɪdiəsi/
A very foolish or stupid action, statement, or behavior.
His decision to invest all his savings in that scheme was pure idiocy.
Idiocy → It is formed from "idio-" (from Greek "idios", meaning one's own or private) and "-cy" (a suffix denoting a state or condition). The word "idiocy" refers to a state of being one's own, often implying a lack of understanding or intelligence, hence the meaning of foolishness or stupidity.
Think of 'idios' meaning 'one's own' to remember that 'idiocy' refers to a state of foolishness that is uniquely one's own.