One providing treatment possibly treats hip (9)
I believe the answer is:
therapist
'one providing treatment' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition. I also know that 'treatment' relates to this answer.
'possibly treats hip' is the wordplay.
'possibly' indicates anagramming the letters.
'treats'+'hip'='treatship'
'treatship' anagrammed gives 'THERAPIST'.
Can you help me to learn more?
(Other definitions for therapist that I've seen before include "Provider of relieving 57 Across" , "Healer of disease" , "Who can soothe" , "See 21" , "One giving treatment" .)