German car parts arrive for business (8)
I believe the answer is:
commerce
'for business' is the definition.
(I've seen this before)
'german car parts arrive' is the wordplay.
'german car' becomes 'Merc' (Mercedes-Benz).
'parts' means one lot of letters goes inside another (inserted letters separate or part others).
'arrive' becomes 'come' (synonyms).
'merc' inserted within 'come' is 'COMMERCE'.
(Other definitions for commerce that I've seen before include "Traffic" , "Business, industry, trade" , "Buying/selling activity" , "Trading exchanges" , "The buying and selling of goods and services" .)