Fool -- going back to take in a line dance (5)
I believe the answer is:
salsa
'dance' is the definition.
(I've seen this before)
'fool going back to take in a line' is the wordplay.
'fool' becomes 'ass' (ass is a kind of fool**).
'going back' says the letters should be written in reverse.
'to take in' is an insertion indicator.
'line' becomes 'l'.
'ass' in reverse letter order is 'ssa'.
'a'+'l'='al'
'ssa' going around 'al' is 'SALSA'.
(Other definitions for salsa that I've seen before include "that's rather spicy!" , "hot stuff" , "Chilli sauce" , "Steps" , "Cuban dance music or spicy sauce" .)