Rescue imprisoned lawyer described as quite ferocious (6)
I believe the answer is:
savage
'ferocious' is the definition.
(I know that ferocious can be written as savage)
'rescue imprisoned lawyer' is the wordplay.
'rescue' becomes 'save' (saving is a kind of rescuing).
'imprisoned' is an insertion indicator.
'lawyer' becomes 'ag' (I can't explain this - if you can you should give a lot more credence to this answer).
'save' enclosing 'ag' is 'SAVAGE'.
'described as quite' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for savage that I've seen before include "Menacing, uncivilised" , "Wild, uncivilised and dangerous" , "Fierce, uncontrolled" , "Fierce and untamed" , "Feral, vicious" .)