Summary
This quote, taken from Shakespeare's play, Hamlet, means that it is amusing or entertaining to see someone's own plans or devices backfire on them. The phrase "hoisted with his own petard" refers to a small bomb or explosive device. So, when someone is said to be "hoisted with his own petard," it means that they have been caught or harmed by their own trap or scheme. This quote speaks to the irony and satisfaction that can be derived from witnessing someone's own actions lead to their downfall.