whoop it up vs fete

whoop it up is not a noun while fete is a noun.

Word	Noun	Adjective	Verb	Adverb
whoop it up	No	No	Yes	No
fete	Yes	No	Yes	No

As verbs, fete is a hypernym of whoop it up; that is, fete is a word with a broader meaning than whoop it up:

whoop it up: celebrate noisily, often indulging in drinking; engage in uproarious festivities
fete: have a celebration

Other hypernyms of whoop it up include celebrate.

whoop it up (noun)	fete (noun)
	an organized series of acts and performances (usually in one place)
	an elaborate party (often outdoors)

whoop it up (verb)	fete (verb)
celebrate noisily, often indulging in drinking; engage in uproarious festivities	have a celebration