Miss going to a festival (4)
I believe the answer is:
gala
'festival' is the definition.
(thesaurus)
'miss going to a' is the wordplay.
'miss' becomes 'gal' ('gal' can be a synonym of 'miss').
'going to' means one lot of letters go next to another.
'gal'+'a'='GALA'
(Other definitions for gala that I've seen before include "Carnival, fete" , "A festive occasion, perhaps of sporting nature" , "Sports meeting" , "sporting event" , "Prod with the elbow" .)