Rough path taking zigzag course across river (5)
I believe the answer is:
track
'rough path' is the definition.
(I've seen this before)
'zigzag course across river' is the wordplay.
'zigzag course' becomes 'tack' (movement in a zigzagging course or path).
'across' means one lot of letters goes inside another.
'river' becomes 'r' (abbreviation for river).
'tack' going around 'r' is 'TRACK'.
'taking' is the link.
(Other definitions for track that I've seen before include "Follow < course" , "One song on CD?" , "racecourse" , "A prepared course for racing on" , "Number on CD" .)