Trade ban therefore restricts a degree of business (7)
I believe the answer is:
embargo
'trade ban' is the definition.
(I've seen this before)
'therefore restricts a degree of business' is the wordplay.
'therefore' becomes 'ergo' (I've seen this before).
'restricts' is an insertion indicator.
'a degree of business' becomes 'MBA' (Master of Business Administration degree).
'ergo' placed around 'mba' is 'EMBARGO'.
(Other definitions for embargo that I've seen before include "restrict trade" , "Government order imposing a trade barrier" , "Official order forbidding something" , "Block" , "Trade barrier or publication ban" .)