Some seafarers, a long way away (4)
I believe the answer is:
afar
'long way away' is the definition.
(I've seen this in another clue)
'some seafarers a' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'AFAR' can be found hidden inside 'seafarers a'.
(Other definitions for afar that I've seen before include "At a distance (literary)" , "(From/at) a great distance" , "Many a mile" , "Remote" , "Inhabitant of Ethiopia" .)