Nouns

(n)juniorterm of address for a disrespectful and annoying male“look here, junior, it's none of your business”
(n)juniora third-year undergraduate
(n)juniorthe younger of two persons“she is two years my junior”

Adjectives

(a)junioryounger; lower in rank; shorter in length of tenure or service
(s)junior, third-year, next-to-lastused of the third or next to final year in United States high school or college“the junior class”, “a third-year student”
(s)juniorincluding or intended for youthful persons“a junior sports league”, “junior fashions”