Join a new sailor (6)
I believe the answer is:
seaman
'sailor' is the definition.
(seaman is a kind of sailor)
'join a new' is the wordplay.
'join' becomes 'seam' (seaming is a kind of joining).
'a new' becomes 'an' (I've seen this in other clues).
'seam'+'an'='SEAMAN'
(Other definitions for seaman that I've seen before include "A manse (anag.)" , "Mariner" , "crew member" , "Sailor" .)