"At speed" can be synonymous with words and phrases such as rapidly, briskly, swiftly, quickly, fleetly, expeditiously, hastily, and at a fast pace. These terms all convey a sense of urgency and speed, whether it be in regards to movement, thought, or action. They can be used interchangeably depending on the context and tone of the sentence. For example, a race car driver might say "I need to drive at speed to win this race," while a manager might say "We need to complete this project expeditiously to meet our deadline." Regardless of the variation used, the meaning remains the same: to perform a task or action quickly and efficiently.