spice up vs flavor

spice up is not a noun while flavor is a noun.

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

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

Other hypernyms of spice up include flavour, season.

spice up (noun)	flavor (noun)
	the taste experience when a savoury condiment is taken into the mouth
	(physics) the six kinds of quarks
	the general atmosphere of a place or situation and the effect that it has on people

spice up (verb)	flavor (verb)
make more interesting or flavorful	lend flavor to
add herbs or spices to