A lass animated by dance music (5)
I believe the answer is:
salsa
'dance music' is the definition.
(I know that salsa is a type of dance music)
'a lass animated by' is the wordplay.
'animated' indicates anagramming the letters.
'by' says to put letters next to each other.
'lass' with letters rearranged gives 'sals'.
'a' after 'sals' is 'SALSA'.
(Other definitions for salsa that I've seen before include "dressing" , "Spicy tomato sauce" , "Latin American dance music" , "fling?" , "Sauce; Afro-Cuban dance" .)