Nothing on English river (4)
I believe the answer is:
nile
'river' is the definition.
(I know that Nile is a river)
'nothing on english' is the wordplay.
'nothing' becomes 'nil' (eg nil is zero in football).
'on' means one lot of letters go next to another (in a down clue, letters appear on others).
'english' becomes 'E' (abbreviation).
'nil'+'e'='NILE'
(Other definitions for nile that I've seen before include "River that's Blue and White" , "River at Luxor" , "Cleopatra's river" , "River associated with Cleopatra" , "Long river" .)