Meaning

• An amusing story.

• Something said or done for amusement, not in seriousness.

  "It was a joke!"

• The root cause or main issue, especially an unexpected one

• A laughably worthless thing or person; a sham.

  "The president was a joke."

Meaning

• To do or say something for amusement rather than seriously.

  "I didn’t mean what I said — I was only joking."

• (intransitive, followed by with) To dupe in a friendly manner for amusement; to mess with, play with.

  "Relax, man, I'm just joking with you."

• To make merry with; to make jokes upon; to rally.

  "to joke a comrade"