v.1. To support something with or as if with a prop: I propped up the leg of my desk with some cardboard to keep it from wobbling. She sat down in the chair and propped her feet up on the table. He propped the ladder up against the wall and climbed up to the roof.
2. To provide temporary or partial support to something that is failing or needs assistance: Foreign investors propped up the currency by purchasing more government bonds. The company would go bankrupt if the government didn't prop it up with special tax breaks.