The noun junior has 4 senses (first 3 from tagged texts)
1. (3) junior -- (term of address for a disrespectful and annoying male; "look here, junior, it's none of your business")
2. (2) junior -- (a third-year undergraduate)
3. (1) junior -- (the younger of two men)
4. Junior, Jr, Jnr -- (a son who has the same first name as his father)
Overview of adj junior
The adj junior has 3 senses (first 2 from tagged texts)
1. (3) junior -- (younger; lower in rank; shorter in length of tenure or service)
2. (2) junior, third-year, next-to-last -- (used of the third or next to final year in United States high school or college; "the junior class"; "a third-year student")
3. junior -- (including or intended for youthful persons; "a junior sports league"; "junior fashions")