Not a square dance presumably? (4)
I believe the answer is:
'dance presumably?' is the definition.
'ball' can be an answer for 'dance' (I've seen this before). I am unsure of the 'presumably?' bit.
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for ball that I've seen before include "Sphere for sport" , "Orb" , "Formal social event" , "Perhaps a bouncer < 's clog" , "Old song: 'After the .... was over'" .)