noun

• (botany) A particularly notable member of a plant species, such as one of great size.
  "Pictured above is an actual photograph of a Regal Lily that famed all over the world. It's a champion plant—because in one season it produced a total of 89 blooms from one bulb, an amazing record among lilies."

adj

• (attributive) Acting as a champion; having defeated all one's competitors.
  "a champion bodybuilder"
• (attributive) Excellent; beyond compare.
• (predicative, Ireland, British, dialect) Excellent; brilliant; superb; deserving of high praise.
  ""That rollercoaster was champion," laughed Vinny."

verb

• (transitive) To promote, advocate, or act as a champion for (a cause, etc.).
  "While obviously championing the Bluebell [Railway], Beardmore is keen for the 'big railway' to consider utilising what preserved railways can provide."
• (obsolete, transitive) To challenge.