noun (n)

• a feeling of strong eagerness (usually in favor of a person or cause)(noun.feeling)

  Example:
  They were imbued with a revolutionary ardor.
  

  Synonym:
  ardour, elan, zeal
  

  source: wordnet30
• intense feeling of love(noun.feeling)

  Synonym:
  ardour
  

  source: wordnet30
• feelings of great warmth and intensity(noun.feeling)

  Example:
  He spoke with great ardor.
  

  Synonym:
  ardour, fervency, fervidness, fervor, fervour, fire
  

  source: wordnet30
• Heat, in a literal sense; as, the ardor of the sun's rays.(noun)

  source: webster1913