Party fun beginning - is tea being served? (6)
I believe the answer is:
fiesta
'party' is the definition.
(thesaurus)
'fun beginning is tea being served?' is the wordplay.
'beginning' indicates taking the first letters.
'being served?' indicates anagramming the letters (I've seen 'served' mean this).
The first letter of 'fun' is 'f'.
'is'+'tea'='istea'
'istea' is an anagram of 'iesta'.
'f'+'iesta'='FIESTA'
(Other definitions for fiesta that I've seen before include "celebration abroad" , "Outdoor celebration" , "Latin American celebration" , "Continental knees-up" , "foreign holiday" .)