Dance very unnecessary in party (4)
I believe the answer is:
reel
'dance' is the definition.
(I know that reel is a type of social dancing)
'unnecessary in party' is the wordplay.
'unnecessary in' becomes 'ree' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'party' becomes 'l'.
'ree'+'l'='REEL'
'very' acts as a link.
Can you help me to learn more?
(Other definitions for reel that I've seen before include "Cylinder on which something is wound" , "Dance; feel giddy" , "long stretch of film" , "Film spool" , "Photographer's and anglers spool" .)