Some specified article plugged by seaman (5)
I believe the answer is:
those
'some specified' is the definition.
('those' means certain specified items)
'article plugged by seaman' is the wordplay.
'article' becomes 'the' (the definite article in English).
'plugged by' indicates putting letters inside (plug can mean to block up a gap).
'seaman' becomes 'OS' (short for ordinary seaman).
'the' enclosing 'os' is 'THOSE'.
(Other definitions for those that I've seen before include "the more far out?" , "The (things) there" , "Plural form of that" , "Ethos (anag.)" , "The ones farther away" .)