Club but no ball for a round (4)
I believe the answer is:
disc
'a round' is the definition.
(disc is a kind of round)
'club but no ball' is the wordplay.
'club' becomes 'disco' (I've seen this before).
'but no' is a deletion indicator.
'ball' becomes 'o' (letter resembling a ball).
'disco' with 'o' taken away is 'DISC'.
'for' acts as a link.
(Other definitions for disc that I've seen before include "Body without limbs" , "something moving in the spine" , "Back part" , "One of 33, 45 or 78?" , "Protein-constituent acid" .)