What is the meaning of Junior?

noun

• Term of address for a disrespectful and annoying male.
  • usage: "look here, junior, it's none of your business"
• A third-year undergraduate.
• The younger of two persons.
  • usage: "she is two years my junior"
• A son who has the same first name as his father.
  • synonyms: Jr, Jnr

adjective

• Younger; lower in rank; shorter in length of tenure or service.
• Used of the third or next to final year in United States high school or college.
  • usage: "the junior class"; "a third-year student"
  • synonyms: third-year, next-to-last
• Including or intended for youthful persons.
  • usage: "a junior sports league"; "junior fashions"