noun (n)

• a state or condition free from damage or decay(noun.state)

  source: wordnet30
• the quality of being prudent and sensible(noun.attribute)

  Synonym:
  wisdom, wiseness
  

  source: wordnet30
• the muscle tone of healthy tissue(noun.attribute)

  Synonym:
  firmness
  Antonym:
  unsoundness
  

  source: wordnet30
• The quality or state of being sound; as, the soundness of timber, of fruit, of the teeth, etc.; the soundness of reasoning or argument; soundness of faith.(noun)

  source: webster1913