Here's a breakdown:
* Origin: The word comes from the Irish Gaelic word "malair", meaning "bad" or "evil".
* Usage: It's a playful way to dismiss something as false or unimportant.
* Example: "Don't tell me that story, that's just a bunch of malarkey!"
It's often used in a humorous or light-hearted way, but can also be used to express frustration or annoyance.