There are a variety of different synonyms to describe someone who is "in good health." Some options might include terms like "physically fit," "robust," "well-nourished," "hale," "hearty," or "vigorous." Other possibilities might include adjectives like "spry," "resilient," "energetic," "sturdy," or "strong." Ultimately, the choice of synonym will depend on the specific context in which it is being used and the tone that the writer is trying to convey. Whatever term is chosen, however, the underlying meaning will always convey a sense of well-being, vitality, and physical strength.