Settled business (4)
I believe the answer is:
firm
This clue is a double definition.
'settled' is the first definition.
('firm' can be similar in meaning to 'settled')
'business' is the second definition.
(firm is a kind of business)
(Other definitions for firm that I've seen before include "Stable; business" , "Unyielding; company" , "'Solid, unyielding (4)'" , "Resolved and steady" , "Secure - business partnership" .)