Substitute for some passengers at Zeebrugge (6)
I believe the answer is:
ersatz
'substitute' is the definition.
(I know that ersatz is a type of substitute)
'some passengers at zeebrugge' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'ERSATZ' can be found hidden inside 'passengers at zeebrugge'.
'for' acts as a link.
(Other definitions for ersatz that I've seen before include "Made in imitation - in Germany" , "Imitation or substitute, from German" , "Not real or genuine" , "unnatural" , "Inferior substitute" .)