Zsa Zsa's sister (3)
I believe the answer is:
eva
'zsa zsa's sister' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for eva that I've seen before include "-- Peron, Argentinian First Lady" , "Maria -- Duarte De Peron" , "Girl's name; space walk" , "girl appears" , "Girl's name; extravehicular activity (abbreviation)" .)