noun

• (video games) A video game mode where the action is demonstrated to entice someone to play the game.
  "The barker looks action-packed, but actually playing the game is rather dull."
• (slang, dated) A pistol.
  "Barney, opening a cupboard, brought forth several articles, which he hastily crammed into the pockets. “Barkers for me, Barney," said Toby Crackit. “Here they are,” replied Barney, producing a pair of pistols."

noun

• (historical) A person who removes needed or valuable tree bark, as on a cinnamon or cinchona plantation.
  "The profession of barker has been made largely obsolete by the realization that in most cases saplings can be cultivated far more profitably."
• (obsolete) A tanner.
  "The profession of barker has been made largely obsolete by the introduction of more effective tanning agents, but it lives on as a surname."