1940s dance (9)
I believe the answer is:
jitterbug
'1940s dance' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for jitterbug that I've seen before include "Fast, jerky American dance of the 1940s" , "1940s US dance" , "Nervous person" , "Lively jazz dance of the 1940s" .)