Seaman's condiment
I believe the answer is:
salt
This clue is a double definition.
'seaman's' is the first definition.
(synonyms)
'condiment' is the second definition.
(I've seen this in another clue)
(Other definitions for salt that I've seen before include "Seasoning; old sailor" , "Sea dog" , "Preserve" , "Mariner; sodium chloride" , "Pile up" .)