Idiot – definition of idiot by The Free Dictionary

id·i·ot (ĭd′ē-ət) n. 1. A person who is considered foolish or stupid. 2. A person with profound intellectual disability having a mental age below three years and generally unable to learn connected speech or guard against common dangers. The term belongs to a classification system no longer in use and is now considered offensive. [Middle English …

: https://www.thefreedictionary.com/idiot