Professor Bill a trained medic (8)
I believe the answer is:
academic
'professor' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'bill a trained medic' is the wordplay.
'bill' becomes 'ac' (short for account).
'trained' is an anagram indicator (to train can mean to grow something into a shape).
'medic' with letters rearranged gives 'demic'.
'ac'+'a'+'demic'='ACADEMIC'
Can you help me to learn more?
(Other definitions for academic that I've seen before include "Associated with places of higher learning" , "Of theoretical interest, or scholarly" , "having no bearing on the situation" , "Scholarly - unrealistic" , "This person may be a professor" .)