American mother's with German husband, a noted economist (4,5)
I believe the answer is:
adam smith
'a noted economist' is the definition.
(I've seen this in another clue)
'american mother's with german husband' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'mother's' becomes 'dam's' (female parent of an animal).
'with german' becomes 'mit' ('with' in German).
'husband' becomes 'h' (abbreviation).
'a'+'dams'+'mit'+'h'='ADAM SMITH'
(Other definitions for adam smith that I've seen before include "Economist" , "Moral philosopher" , "The Wealth of Nations author" , "Advocate of free trade" .)