Inflexible, doctor over papers (5)
I believe the answer is:
rigid
'inflexible' is the definition.
('rigid' can be a synonym of 'inflexible')
'doctor over papers' is the wordplay.
'doctor' becomes 'rig' (I've seen this in other clues**).
'over' means one lot of letters go next to another.
'papers' becomes 'id' (identification papers).
'rig'+'id'='RIGID'
(Other definitions for rigid that I've seen before include "Hard" , "Firmly fixed" , "strict" , "completely" , "not relaxing" .)