Relative a German upset over church (5)
I believe the answer is:
niece
'relative' is the definition.
(type of relative)
'a german upset over church' is the wordplay.
'a german' becomes 'ein' ('a' in German).
'upset over' says the letters should be written backwards (knocked over).
'church' becomes 'CE' (abbreviation for Church of England).
'ein' in reverse letter order is 'nie'.
'nie'+'ce'='NIECE'
(Other definitions for niece that I've seen before include "Preparation for curdling milk" , "Criminal" , "A sibling's daughter" , "Daughter of a sibling" , "member of different generation" .)