German city engaged in business enterprise (5)
I believe the answer is:
essen
'german city' is the definition.
(city in Germany)
'engaged in business enterprise' is the wordplay.
'engaged in' says the answer is hidden in the clue.
'ESSEN' can be found hidden inside 'business enterprise'.
(Other definitions for essen that I've seen before include "German industrial centre" , "German place name" , "Industrial centre of the Ruhr" , "Main industrial city of the Ruhr" , "Krupp HQ (Ger.)" .)