What the tabloids call Susan Boyle's badly trained assistant (11)
I believe the answer is:
subordinate
'assistant' is the definition.
(I know that subordinate is a type of assistant)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for subordinate that I've seen before include "Inferior" , "going below" , "Lower in rank" , "Of less importance" , "Dependent" .)