German citizen's fast food (9)
I believe the answer is:
hamburger
I believe this is a double definition.
'german citizen's' is the first definition.
(someone from Hamburg)
'fast food' is the second definition.
(I've seen this before)
(Other definitions for hamburger that I've seen before include "Citizen of Europe" , "Fast-food item" , "beefcake" , "Fried cake of minced beef served on a bun" , "Beef dish from German city" .)