He is six years 'junior' to me. = He is 'junior' to me by six years. [=he is six years younger than I am]
He is six years my 'junior'. [=he is six years younger than I am]
She is a 'junior' partner in the law firm.
(..) - Hey, got you another one. - Thanks. I have a date with Edward Cullen. He's a little old for you, isn't he? No. He's a junior. I'm a junior. I thought you liked the Cullens. I thought you didn't like any of the boys in town. Edward doesn't live in town. Technically. (..)2008 Twilight