alter vs castrate

alter is not a noun while castrate is a noun.

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

As verbs, alter and castrate are synonyms defined as:

Other synonyms of alter include neuter, spay.

alter (noun)	castrate (noun)
	a man who has been castrated and is incapable of reproduction

alter (verb)	castrate (verb)
remove the ovaries of	remove the testicles of a male animal
become different in some particular way, without permanently losing one's or its former characteristics or essence	remove the ovaries of
cause to change; make different; cause a transformation	deprive of strength or vigor
insert words into texts, often falsifying it thereby	edit by omitting or modifying parts considered indelicate
make an alteration to