Here are some examples of how "vigorous" can be used:
For a person:
* "The old man was still surprisingly vigorous for his age."
* "She gave a vigorous handshake."
For an action:
* "He shook his head vigorously."
* "They engaged in a vigorous debate."
For a physical object:
* "The plant had vigorous growth."
* "The engine is in vigorous condition."
Synonyms for vigorous:
* Energetic
* Strong
* Powerful
* Forceful
* Active
* Robust
* Spirited
* Lively
Antonyms for vigorous:
* Weak
* Feeble
* Tired
* Lazy
* Passive