retard vs simpleton

retard and simpleton both are nouns.

Word	Noun	Adjective	Verb	Adverb
retard	Yes	No	Yes	No
simpleton	Yes	No	No	No

As nouns, simpleton is a hypernym of retard; that is, simpleton is a word with a broader meaning than retard:

Other hypernyms of retard include simple.

retard (noun)	simpleton (noun)
a person of subnormal intelligence	a person lacking intelligence or common sense

retard (verb)	simpleton (verb)
lose velocity; move more slowly
cause to move more slowly or operate at a slower rate
slow the growth or development of
be delayed