Capital for Helen's abductor (5)
I believe the answer is:
paris
I believe this is a double definition.
'capital' is the first definition.
(Paris is the capital of France)
'helen's abductor' is the second definition.
(I've seen this in another clue)
'for' acts as a link.
(Other definitions for paris that I've seen before include "Legendary prince" , "City; Juliet's betrothed Count" , "Capital of France" , "Abductor of Helen" , "An American in - -" .)