Ridge on a guitar neck (4)
I believe the answer is:
fret
'ridge on a guitar neck' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for fret that I've seen before include "Worry; wet mist" , "Worry, brood" , "Show anxiety" , "Worry - decoration - part of guitar" , "Mist coming in from the sea" .)