Synonyms for Know ones business:

• adj.

  •competent (adjective)
  • efficient,
  • clever,
  • satisfactory,
  • know the score,
  • polished,
  • up to snuff,
  • adequate,
  • complete,
  • up to it,
  • no slouch,
  • good,
  • fit,
  • au fait,
  • fool,
  • know one's business,
  • there,
  • know one's stuff,
  • decent,
  • suitable,
  • sufficient,
  • on the ball,
  • pertinent,
  • know ins and outs,
  • adapted,
  • paid one's dues,
  • savvy,
  • enough,
  • capable,
  • crisp,
  • proficient,
  • equal,
  • fireball,
  • skilled,
  • up to speed,
  • know the answers,
  • appropriate,
  • all around,
  • being a pistol,
  • endowed,
  • qualified,
  • know the ropes,
  • dynamite.

Antonyms for Know ones business:

• adj.

  • competent
    incapable, inefficient, incompetent, inept, inadequate, unable.