Most Split Second refers to a very small unit of time. The antonyms of Most Split Second can be words like - delayed, prolonged, procrastinated, put off, stalled, sluggish, slow, tardy, halted, and deferred. These words imply that things are not happening quickly, and instead, there is a delay or a lag in progress. While Most Split Second signifies speedy action, its antonyms imply the opposite. These words can come in handy while describing or narrating a situation where things are not happening at the expected speed, or are slow to progress. In essence, Most Split Second's antonyms describe what happens when the speed that it implies is not present.