'The Samurai' cast is unprofessional (10)
I believe the answer is:
amateurish
'unprofessional' is the definition.
(I've seen this before)
'the samurai cast' is the wordplay.
'cast' indicates an anagram.
'the'+'samurai'='thesamurai'
'thesamurai' anagrammed gives 'AMATEURISH'.
'is' acts as a link.
(Other definitions for amateurish that I've seen before include "using little craft, perhaps" , "Rather 31 across" , "Lay" , "Not very professional" , "Inept, unskilful" .)