A timeless Test is a match of Test cricket played under no limitation of time, which means the match is played until one side wins or the match is tied, with theoretically no possibility of a draw. The format means that it is not possible to play defensively for a draw when the allotted time runs out, and delays due to bad weather will not prevent the match ending with a positive result. It also means that there is far less reason for a side to declare an innings, since time pressure should not affect the chances of winning the game.
Although the format should guarantee a result, it was ultimately abandoned as it was impossible to predict with any certainty when a match would be finished, making scheduling and commercial aspects difficult. In the modern era teams often play back-to-back Tests in consecutive weeks, something that would be impossible without the five-day limit.