The definition of an idiot is a fool or stupid person.(noun)
An example of an idiot is a person who thinks it's safe to play in traffic.
See idiot in Webster's New World College Dictionary
Origin: ME idiote < OFr < L idiota, ignorant and common person < Gr idiōtēs, layman, ignorant person < idios, one's own, peculiar: see idio-
See idiot in American Heritage Dictionary 4
Origin: Middle English, ignorant person
Origin: , from Old French idiote
Origin: , from Latin idiōta
Origin: , from Greek idiōtēs, private person, layman
Origin: , from idios, own, private; see s(w)e- in Indo-European roots.
Learn more about idiot