Antonyms:
* Uprightness: Standing tall, strong, and confident.
* Vigor: Strength, energy, and vitality.
* Health: A state of well-being and physical soundness.
* Resilience: The ability to recover quickly from difficulties.
* Exuberance: Great enthusiasm, happiness, and vitality.
Synonyms:
* Collapse: To fall down suddenly, usually from exhaustion or injury.
* Weakness: A lack of strength or power.
* Dejection: A state of low spirits and hopelessness.
* Fatigue: Extreme tiredness.
* Exhaustion: Complete loss of energy and strength.
The specific antonym or synonym that best fits will depend on the context in which you are using the word "prostration."