Move effortlessly (4)
'move effortlessly' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for glide that I've seen before include "Make an unpowered flight" , "Fly without power" , "Move smoothly, as a sailplane" , "Gelid (anag.)" , "Move smoothly and effortlessly" .)
(Other definitions for sail that I've seen before include "Navigate" , "Leave harbour" , "Begin a voyage" , "Go by boat" , "Go by water" .)