Beat inferior at a dance (7)
I believe the answer is:
lambada
'dance' is the definition.
(Brazilian dance)
'beat inferior at a' is the wordplay.
'beat' becomes 'lam' (I've seen this before).
'inferior' becomes 'bad' (similar in meaning).
'at' is a charade indicator (letters next to each other).
'lam'+'bad'+'a'='LAMBADA'
(Other definitions for lambada that I've seen before include "dance in South America" , "number of Brazilian revellers" , "Fast Brazilian 3 dn" , "Erotic Brazilian dance" , "sexy dance" .)