spice up vs alter

spice up and alter both are verbs.

Word	Noun	Adjective	Verb	Adverb
spice up	No	No	Yes	No
alter	No	No	Yes	No

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

Other hypernyms of spice up include change, modify.

spice up (verb)	alter (verb)
make more interesting or flavorful	remove the ovaries of
add herbs or spices to	become different in some particular way, without permanently losing one's or its former characteristics or essence
	cause to change; make different; cause a transformation
	insert words into texts, often falsifying it thereby
	make an alteration to