The word "speediest" is often used when talking about something that can be done quickly. However, there are other words that can be used instead of "speediest" to convey the same meaning. Some synonyms for "speediest" include "fastest," "quickest," "swiftest," and "most rapid." These words can be used interchangeably with "speediest" depending on the context and tone of the sentence. It is always important to choose words that accurately convey the desired meaning and tone of your message, and by using synonyms like these, you can add a bit of variety and interest to your writing.