In a perfect world I do business and play alternately (7)
I believe the answer is:
ideally
'in a perfect world' is the definition.
(I've seen this before)
'i do business and play alternately' is the wordplay.
'do business' becomes 'deal' (I've seen this before).
'and' says to put letters next to each other.
'alternately' indicates alternate letters.
The alternate letters of 'play' are 'ly'.
'i'+'deal'+'ly'='IDEALLY'
(Other definitions for ideally that I've seen before include "In the best possible way or circumstances" , "In the best of all possible worlds" , "in optimal way" , "for preference" , "for best results" .)