Shout 'Party!' (4)
I believe the answer is:
rave
This clue is a double definition.
'shout' is the first definition.
(thesaurus)
'party' is the second definition.
(thesaurus)
(Other definitions for rave that I've seen before include "Rant about an all-night dance party?" , "Talk incoherently" , "Enthusiastically favourable review" , "Talk with extreme enthusiasm or wild delirium" , "Pop dance party" .)