Narrow channel — not winding, by the sound of it (6)
I believe the answer is:
strait
'narrow channel' is the definition.
(I've seen this in another clue)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for strait that I've seen before include "Narrow kind of traits" , "Narrow passage joining two large areas of water" , "Narrow stretch of water as at Gibraltar" , "Narrow sorts of traits" , "Narrow strip of water between two larger ones" .)