Big deal has two moves (2,4)
I believe the answer is:
so what
'big deal' is the definition.
(similar expressions of apathy)
'has two moves' is the wordplay.
'moves' indicates anagramming the letters.
'has'+'two'='hastwo'
'hastwo' is an anagram of 'SO WHAT?'.
(Other definitions for so what that I've seen before include "I don't care" , "I'm not interested" , "It's unimportant, right?" , "is that surprising?" , "Does it make any difference" .)