Longest river in China (7)
I believe the answer is:
yangtze
'longest river in china' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for yangtze that I've seen before include "Longest river of Asia" , "Chinese river (Z, not S)" , "Longest river in China" , "Chinese river, aka Chang Jiang" , "here (together with China Girl)?" .)