Sailor’s last resort (4)
I believe the answer is:
salt
'sailor's' is the definition.
(salt is a kind of sailor)
'last resort' is the wordplay.
'resort' is an anagram indicator.
'last' is an anagram of 'SALT'.
(Other definitions for salt that I've seen before include "A defence against ice" , "Pile up" , "Sea dog" , "Crystalline substance for the table" , "Preservative" .)