noun (n)

• the quality of being slight or inadequate(noun.attribute)

  Example:
  He knew the slenderness of my wallet.
  The slenderness of the chances that anything would be done.
  The slenderness of the evidence.
  

  source: wordnet30
• relatively small dimension through an object as opposed to its length or width(noun.attribute)

  Synonym:
  tenuity, thinness
  Antonym:
  thickness
  

  source: wordnet30
• the property of an attractively thin person(noun.attribute)

  Synonym:
  slightness, slimness
  

  source: wordnet30