Target six clubs with German backing (6)
I believe the answer is:
victim
'target' is the definition.
(eg the target of a crime)
'six clubs with german backing' is the wordplay.
'six' becomes 'VI' (Roman numerals).
'clubs' becomes 'c' (abbreviation used in card games such as bridge).
'with german' becomes 'mit' ('with' in German).
'backing' says the letters should be written in reverse.
'mit' backwards is 'tim'.
'vi'+'c'+'tim'='VICTIM'
(Other definitions for victim that I've seen before include "Fall guy" , "One made to suffer" , "Person injured or killed in accident" , "Person killed, hurt or abused" , "Person who has suffered" .)