River -- some deny that will rise (4)
I believe the answer is:
tyne
'river' is the definition.
(I've seen this before)
'some deny that will rise' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'rise' says the letters should be written in reverse.
'enyt' is hidden in the letters of 'deny that will'.
'enyt' reversed gives 'TYNE'.
(Other definitions for tyne that I've seen before include "River of northeast England" , "North of England river" , "River of Northumberland" , "Newcastle's river" , "English river" .)