Jib or mizzen (4)
I believe the answer is:
sail
This clue is a double definition.
'jib' is the first definition.
(I know that jib is a more specific form of the action sail)
'mizzen' is the second definition.
(thesaurus)
(Other definitions for sail that I've seen before include "It catches the wind on a mast" , "Travel by ship" , "Canvas on board" , "Go by boat" , "Go by water" .)