Train as fantastic skilled manual worker (7)
I believe the answer is:
artisan
'skilled manual worker' is the definition.
(I've seen this before)
'train as fantastic' is the wordplay.
'fantastic' indicates an anagram (a fantastic or improbable ordering of the letters).
'train'+'as'='trainas'
'trainas' anagrammed gives 'ARTISAN'.
(Other definitions for artisan that I've seen before include "Crafty sort" , "Handy worker" , "Skilled tradesman" , "Skilled craftsperson" , "man with skill" .)