fete vs whoop it up

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

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

As verbs, whoop it up is a hyponym of fete; that is, whoop it up is a word with a more specific, narrower meaning than fete:

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

Other hyponyms of fete include jubilate, jollify, make happy, make merry, make whoopee, racket, revel, wassail, party, receive.

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

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