adj

• (not comparable) Beyond what is due, usual, expected, or necessary; extraneous; additional; supernumerary.
  "I don't mind doing some extra work, as long as I get extra pay."
• (not comparable, dated) Extraordinarily good; superior.
• (comparable, slang) Over the top; going beyond what is normal or appropriate, often in a dramatic manner.
  "You unfollowed her for posting cat memes? You're so extra!"

adv

• (informal) To an extraordinary degree.
  "That day he ran to school extra fast."

noun

• (cricket) A run scored without the ball having hit the striker's bat - a wide, bye, leg bye or no ball.
• (acting) A supernumerary or walk-on in a film or play.
• (slang) The state or trait of being over the top, of behaving in an overly dramatic manner.
  "Stop! I can't deal with all your extra today!"
• (Singapore, military, countable) A day of extra duties (often, over the weekends) in camp, as a form of punishment. Used in the phrase “to sign extra”, meaning one has been assigned extras as punishment.