idiot vs simple

idiot and simple both are nouns.

Word	Noun	Adjective	Verb	Adverb
idiot	Yes	No	No	No
simple	Yes	Yes	No	No

As nouns, simple is a hypernym of idiot; that is, simple is a word with a broader meaning than idiot:

Other hypernyms of idiot include simpleton.

idiot (noun)	simple (noun)
a person of subnormal intelligence	a person lacking intelligence or common sense
	any herbaceous plant having medicinal properties

idiot (adjective)	simple (adjective)
	(botany) of leaf shapes; of leaves having no divisions or subdivisions
	having few parts; not complex or complicated or involved
	easy and not involved or complicated
	exhibiting childlike simplicity and credulity
	unornamented
	lacking mental capacity and subtlety
	apart from anything else; without additions or modifications