Definitions of junior
(UK also: junior barrister) a barrister who is not a Queen's Counsel
You will also be instructed as a junior assisting a Queen's Counsel in larger cases and in advisory work.
(UK also: junior barrister) a barrister who is appearing with a leader
I will lead the defence with Mr Smith as my junior.
younger or lower in rank or importance
I worked for Lee when he was a young partner in our Moscow office and I was a junior associate.