Sails through (4)
I believe the answer is:
aces
'sails through' is the definition.
('ace' can be a synonym of 'sail through')
This is all the clue.
(Other definitions for aces that I've seen before include "Two will make deuce" , "Experts (in their field)" , "They're high and low on cards" , "holes in one" , "Honours" .)