The phrase "most volitant" refers to something that is very flighty or likely to fly away. Some antonyms for this phrase could include "grounded," "motionless," "stationary," "rooted," "immovable," "fixed," or "stable." These words suggest a sense of stability or groundedness, which is the opposite of the lightness and freedom implied by "volitant." Other antonyms could include terms like "heavy," "weighty," "burdened," or "anchored," which imply a sense of inertia or being held back. All of these antonyms offer a different perspective on the idea of motion and stability, and they provide a useful contrast to the ideas implied by "most volitant.