The lawyer's employer has the right to appear in court (6)
I believe the answer is:
client
'the lawyer's employer' is the definition.
'client' can be an answer for 'employer' (I have seen 'Employer of professional' mean 'client' so perhaps 'employer' could also mean 'client'). I'm not sure about the 'the lawyer's' bit.
'the right to appear in court' is the wordplay.
'the right' becomes 'lien' (legal right).
'to appear in' is an insertion indicator.
'court' becomes 'ct' (abbreviation used in road names).
'lien' placed inside 'ct' is 'CLIENT'.
'has' acts as a link.
Can you help me to learn more?
(Other definitions for client that I've seen before include "Professional's customer" , "person lawyer represents" , "Computer program" , "Professional person's customer" , "Customer for professional service" .)