Registered occupational therapist hoax upset academic (6)
I believe the answer is:
doctor
'academic' is the definition.
(doctor can mean someone with a doctorate)
'registered occupational therapist hoax upset' is the wordplay.
'registered occupational therapist' becomes 'ROT' (abbreviation).
'hoax' becomes 'cod' (I've seen this before).
'upset' shows that the letters should be reversed in order.
'rot'+'cod'='rotcod'
'rotcod' in reverse letter order is 'DOCTOR'.
(Other definitions for doctor that I've seen before include "Medical specialist" , "Who perhaps" , "GP" , "An apple a day keeps him away" , "Tamper with - falsify - one of the 14 films" .)