Trains a new workman (7)
I believe the answer is:
artisan
'workman' is the definition.
(I have seen 'Skilled workman' mean 'artisan' so perhaps 'workman' could also mean 'artisan')
'trains a new' is the wordplay.
'new' is an anagram indicator.
'trains'+'a'='trainsa'
'trainsa' is an anagram of 'ARTISAN'.
(Other definitions for artisan that I've seen before include "Journeyman" , "Crafty sort" , "craftsman of his trade" , "Skilled workman" , "one in command of craft?" .)