simple vs simplicity

simple and simplicity both are nouns.

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

simple (noun)	simplicity (noun)
a person lacking intelligence or common sense	freedom from difficulty or hardship or effort
any herbaceous plant having medicinal properties	lack of ornamentation
	the quality of being simple or uncompounded
	absence of affectation or pretense
	a lack of penetration or subtlety

simple (adjective)	simplicity (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