The term "most sluggard" refers to the laziest or most idle individual. Some antonyms for this term could include hardworking, industrious, diligent, proactive, energetic, and productive. These words describe individuals who are actively engaged in the tasks at hand and put in the time and effort required to achieve their goals. By contrast, a sluggard is someone who is lethargic, apathetic, and unmotivated to work. When you use antonyms for "most sluggard," you are describing a person's positive attributes and qualities that are desired in the workplace and in life in general.