Pass a bend or twist in the river (5)
I believe the answer is:
douro
'river' is the definition.
(I've seen this before)
'pass a bend or twist in' is the wordplay.
'pass' becomes 'do' (doing is a kind of passing).
'a bend' becomes 'U' (a U-bend is a kind of bend - pipe under sink).
'twist' indicates anagramming the letters (a twisted or distorted version of the letters).
'in' indicates putting letters inside.
'u'+'or'='uor'
'uor' with letters rearranged gives 'our'.
'do' placed around 'our' is 'DOURO'.
'the' acts as a link.
(Other definitions for douro that I've seen before include "Hollow bubbling sound" , "Iberian river" , "European runner" .)