A party associated with royal expert, cute (8)
I believe the answer is:
adorable
'cute' is the definition.
(I've seen this in another clue)
'a party associated with royal expert' is the wordplay.
'party' becomes 'do' (do can informally mean a party).
'associated with' is a charade indicator (letters next to each other).
'royal' becomes 'r' (common abbreviation e.g. RM - Royal Marine).
'expert' becomes 'able' (able can mean expert or talented).
'a'+'do'+'r'+'able'='ADORABLE'
(Other definitions for adorable that I've seen before include "Attractive - captivating" , "Very pleasing" , "Inspiring great affection" , "Worthy of worship" , "Winsome" .)