Danseur dancing apart (7)
I believe the answer is:
asunder
'apart' is the definition.
(synonyms)
'danseur dancing' is the wordplay.
'dancing' indicates anagramming the letters.
'danseur' with letters rearranged gives 'ASUNDER'.
(Other definitions for asunder that I've seen before include "separately" , "Apart - in pieces" , "(Rent) apart" , "(Split) apart" , "(Break) apart" .)