Wildly beat celery no end, have a party! (9)
I believe the answer is:
celebrate
'have a party' is the definition.
(I've seen this before)
'wildly beat celery no end' is the wordplay.
'wildly' indicates anagramming the letters.
'no end' means to remove the last letter.
'beat'+'celery'='beatcelery'
'beatcelery' with its final letter removed is 'beatceler'.
'beatceler' anagrammed gives 'CELEBRATE'.
(Other definitions for celebrate that I've seen before include "Honour; make famous" , "Rejoice or commemorate" , "Rejoice - observe - perform" , "Be festive" , "Mark special event with festivities" .)