Fake doctor sectioned son unseen (6)
I believe the answer is:
deceit
'fake' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for deceit that I've seen before include "Guile" , "Act of deliberate misleading" , "Fraud, falseness" , "Hypocrisy" , "Dishonesty, misrepresentation" .)