adjective (a)

• not saturated; capable of dissolving more of a substance at a given temperature(adj.all)

  Example:
  An unsaturated salt solution.
  

  Antonym:
  concentrated, saturated
  

  source: wordnet30
• used of a compound (especially of carbon) containing atoms sharing more than one valence bond(adj.all)

  Example:
  Unsaturated fats.
  

  Antonym:
  saturated
  

  source: wordnet30
• (of color) not chromatically pure; diluted(adj.all)

  Example:
  An unsaturated red.
  

  Antonym:
  pure, saturated
  

  source: wordnet30
• Capable of absorbing or dissolving to a greater degree; as, an unsaturated solution.(adjective)

  source: webster1913