What are the antonyms for Offgoing?

• n.

  • exit
  • arrival
  ,
  • arriving
  ,
  • birth
  ,
  • coming
  ,
  • entering
  ,
  • entrance
  ,
  • hello
  ,
  • stay
  .

Well up on is typically used to describe someone who possesses a great amount of knowledge or expertise on a particular subject. However, there are several antonyms for this phrase...