Australia's largest lake (4)
I believe the answer is:
eyre
'australia's largest lake' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for eyre that I've seen before include "lake, down under" , "Jane . . . ., . . . . Square" , "See 17 Across" , "Galway square" , "one loved by Rochester" .)