1. Adjective.  Not possible, not able to be done.
  2. Adjective.  (colloquial) Of a person, very difficult to deal with.
  3. Noun.  An impossibility.
  4. Noun.  (uncountable) (qualifier, with definite article) That which seems impossible.

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This entry was last updated on RefTopia from its source on 3/20/2012.