Mariners, sailors (9)
I believe the answer is:
seafarers
This clue is a double definition.
'mariners' is the first definition.
(I know this)
'sailors' is the second definition.
(seafarer is a kind of sailor)
(Other definitions for seafarers that I've seen before include "Description fitting salts" , "Jack-tars, old salts" , "Mariners, sailors" .)