The word "prorogates" means to extend or prolong a period of time, but its antonyms are those that indicate a decrease or reduction in time. Some of the antonyms of prorogates include abridges, curtails, shortens, truncates, terminates, and ends. Abridging means to shorten or cut down a long period of time, while curtailing involves the reduction of the length or duration of something. Shortening implies reducing the amount of time needed to complete a task or activity, and truncating refers to the reduction of the length or extent of anything. Terminating or ending suggests putting an end to a process, event or activity, or bringing it to a close.