The sailors sounded cocky (4)
I believe the answer is:
crew
This clue is a double definition.
'the sailors' is the first definition.
(as in a ship's crew)
'sounded cocky' is the second definition.
(ie made a cock's crow)
(Other definitions for crew that I've seen before include "This male hair style is closely cropped" , "Ship's sailors" , "A kind of short cut" , "Provided a wake-up call" , "Those who man a ship or aircraft" .)