know-all

know-all

A person who acts like they are smarter than everyone else. Primarily heard in UK, Australia. There is nothing more annoying than working with a know-all who constantly tries to outdo everyone else.
Farlex Dictionary of Idioms.
See also:
  • be a pain in the neck
  • be (strictly) for the birds
  • know better
  • know better than
  • enough to plague a saint
  • a thorn in (one's) flesh
  • at bottom
  • butt-wipe
  • a-hole
  • be rid of somebody/something