The phrase "most sylphlike" describes an individual who is graceful, slender, and light. Antonyms for this phrase might include words that describe someone who is heavy, clumsy, or awkward. Some possible antonyms for "most sylphlike" might include "burly," "chubby," "clumsy," "stocky," or "brawny." These words describe individuals who have a more muscular or bulky physique and are less graceful and delicate in their movements. While "most sylphlike" suggests a certain elegance and finesse, antonyms for this phrase suggest a more robust and less delicate physicality.