Go yachting (4)
I believe the answer is:
sail
'go yachting' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sail that I've seen before include "Put to sea in yacht" , "Fabric on a mast" , "Travel on water propelled by wind" , "Travel by boat" , "Glide along" .)