noun (n)

• the property of being an amount by which something is less than expected or required(noun.attribute)

  Example:
  New blood vessels bud out from the already dilated vascular bed to make up the nutritional deficit.
  

  Synonym:
  shortage, shortfall
  

  source: wordnet30
• a deficiency or failure in neurological or mental functioning(noun.state)

  Example:
  The people concerned have a deficit in verbal memory.
  They have serious linguistic deficits.
  

  source: wordnet30
• (sports) the score by which a team or individual is losing(noun.quantity)

  Antonym:
  lead
  

  source: wordnet30
• an excess of liabilities over assets (usually over a certain period)(noun.possession)

  Example:
  Last year there was a serious budgetary deficit.
  

  source: wordnet30
• Deficiency in amount or quality; a falling short; lack; as, a deficit in taxes, revenue, etc.(noun)

  source: webster1913