Freedom of movement allowed by joint chamber (9)
I believe the answer is:
elbowroom
'freedom of movement allowed' is the definition.
I can't tell whether this defines the answer.
'by joint chamber' is the wordplay.
'by' means one lot of letters go next to another.
'joint' becomes 'elbow joint' (joint of the body).
'chamber' becomes 'room' (I've seen this before).
'elbow'+'room' is 'ELBOWROOM'.
Can you help me to learn more?
(Other definitions for elbowroom that I've seen before include "Lower boom to make working space" , "Leeway" , "Enough scope to function" , "Space to function" , "Enough space to work or move in - flex arm" .)