Doubled up, is able to dance (6)
I believe the answer is:
cancan
'dance' is the definition.
(cancan is a kind of dance)
'doubled up is able to' is the wordplay.
'doubled up' indicates the doubling of some letters.
'is able to' becomes 'can' (if you can do something you are able to do it).
'can' doubled is 'CANCAN'.
(Other definitions for cancan that I've seen before include "Parisian stage dance" , "Leg-kicking dance" , "Daring French dance, doubly permissive" , "Lively stage dance, doubly permissive" , "High-kicking French dance, once considered naughty" .)