There are many synonyms for the phrase "toning up," which refers to the process of firming and strengthening muscles. Some alternative phrases include building muscle, defining muscles, sculpting the body, shaping up, and getting fit. Other phrases that convey similar meanings are strength training, resistance training, weight lifting, bodyweight exercises, and circuit training. These all involve various exercises and routines that focus on specific muscle groups and can increase strength and muscle definition. Overall, there are many ways to tone up and improve physical fitness, and exploring different workouts and incorporating variety into one's exercise routine can lead to better results.