Major Chinese river (7)
I believe the answer is:
yangtze
'major chinese river' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for yangtze that I've seen before include "Chinese river (Z, not S)" , "Longest Asian river" , "Major Chinese river" , "Longest river of Asia" , "Chinese river; Tyne zag (anag.)" .)