Youngster joins an attorney for a dance (7)
I believe the answer is:
lambada
'for a dance' is the definition.
(Brazilian dance)
'youngster joins an attorney' is the wordplay.
'youngster' becomes 'lamb' (a lamb is a young sheep).
'joins' is a charade indicator (letters next to each other).
'an' becomes 'a'.
'attorney' becomes 'D.A.' (District Attorney).
'lamb'+'a'+'da'='LAMBADA'
(Other definitions for lambada that I've seen before include "raunchy dance" , "few steps?" , "number of Brazilian revellers" , "rhythmic Latin American dance" , "Latin-American dance" .)