slow down vs alter

slow down and alter both are verbs.

Word	Noun	Adjective	Verb	Adverb
slow down	No	No	Yes	No
alter	No	No	Yes	No

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

Other hypernyms of slow down include change, modify.

slow down (verb)	alter (verb)
become less tense, rest, or take one's ease	remove the ovaries of
lose velocity; move more slowly	become different in some particular way, without permanently losing one's or its former characteristics or essence
become slow or slower	cause to change; make different; cause a transformation
reduce the speed of	insert words into texts, often falsifying it thereby
cause to proceed more slowly	make an alteration to