The way to business sure rocky (6)
I believe the answer is:
course
'the way' is the definition.
(course is a kind of way)
'business sure rocky' is the wordplay.
'business' becomes 'co' (short for company).
'rocky' indicates anagramming the letters.
'sure' anagrammed gives 'urse'.
'co'+'urse'='COURSE'
'to' acts as a link.
(Other definitions for course that I've seen before include "Route of the race" , "may be instructive" , "Route; lectures" , "Each separate part of meal" , "Route; dish" .)