Ball made square amazingly (10)
I believe the answer is:
masquerade
'ball' is the definition.
(masquerade ball is a kind of ball)
'made square amazingly' is the wordplay.
'amazingly' indicates anagramming the letters.
'made'+'square'='madesquare'
'madesquare' is an anagram of 'MASQUERADE'.
(Other definitions for masquerade that I've seen before include "The wearing of disguise" , "Pretend to be someone one is not" , "Dress up" , "Deception" , "where everyone's wearing the veil" .)