Let's dance in pants in private (11)
I believe the answer is:
clandestine
'private' is the definition.
(I've seen this before)
'let's dance in pants' is the wordplay.
'pants' indicates an anagram (UK informal term for 'nonsense' or 'rubbish').
'lets'+'dance'+'in'='letsdancein'
'letsdancein' is an anagram of 'CLANDESTINE'.
'in' is the link.
(Other definitions for clandestine that I've seen before include "through the backdoor" , "Private" , "Done secretly" , "Concealed" , "Undercover" .)