Researcher’s appointment with medic (7)
I believe the answer is:
postdoc
'researcher's' is the definition.
(someone doing postdoctoral research)
'appointment with medic' is the wordplay.
'appointment' becomes 'post' (appointment to a job).
'with' says to put letters next to each other.
'medic' becomes 'doc' (doctor).
'post'+'doc'='POSTDOC'
(Other definitions for postdoc that I've seen before include "Researcher" , "Someone doing advanced research" .)