retard vs alter

retard is a noun but alter is not a noun.

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

As verbs, alter is a hypernym of retard; that is, alter is a word with a broader meaning than retard:

Other hypernyms of retard include change, modify.

retard (noun)	alter (noun)
a person of subnormal intelligence

retard (verb)	alter (verb)
lose velocity; move more slowly	remove the ovaries of
cause to move more slowly or operate at a slower rate	become different in some particular way, without permanently losing one's or its former characteristics or essence
slow the growth or development of	cause to change; make different; cause a transformation
be delayed	insert words into texts, often falsifying it thereby
	make an alteration to