Makes fast (5)
'makes fast' is the definition.
('secure' can be a synonym of 'make fast')
This is all the clue.
(Other definitions for secures that I've seen before include "Makes firmly attached" , "Makes safe through rescues" , "Guarantees" , "Closes, fortifies" , "Ties down" .)
'makes fast' is the definition.
(mooring is a kind of making fast)
This is the entire clue.
(Other definitions for moors that I've seen before include "wild places" , "Secures" , "Berths" , "Ties up (vessel)" , "Conquerors once" .)