The antonym for the word "unhealthiest" is "healthiest." The term "healthiest" implies to be in perfect physical and mental condition, without any illness or disease. It also means being fit, active, and adopting a healthy lifestyle by eating nutritious food, exercising regularly, and avoiding unhealthy habits. Healthier habits lead to a better quality of life, making you look and feel good inside out. Apart from healthiest, some other synonyms for the term include fittest, wholesome, robust, and sound. These words signify the positive aspects of leading a healthy life and encourage people to work on self-improvement for better overall health.