A hidden or disguised opening, usually in the floor, used for escape or for accessing a hidden place.

छिपा हुआ दरवाजा तंत्र

English Usage: The spy disappeared through a trap door mechanism in the stage.

Hindi Usage: जासूस मंच पर गुप्त दरवाज़े की प्रणाली से गायब हो गया।