River of Pakistan (5)
I believe the answer is:
indus
'river of pakistan' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for indus that I've seen before include "River of Southern Asia" , "South Asian river" , "River giving its name to an early civilisation" , "River flowing from Tibet to the Arabian Sea" , "Main river of Pakistan" .)