simple mindedness vs simplicity

simple mindedness and simplicity both are nouns.

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

As nouns, simple mindedness and simplicity are synonyms defined as:

Other synonyms of simple mindedness include simpleness.

simple mindedness (noun)	simplicity (noun)
a lack of penetration or subtlety	freedom from difficulty or hardship or effort
	lack of ornamentation
	the quality of being simple or uncompounded
	absence of affectation or pretense
	a lack of penetration or subtlety