noun (n)

• the feeling of being displeased and discontent(noun.feeling)

  Example:
  He was never slow to express his dissatisfaction with the service he received.
  

  Antonym:
  satisfaction
  

  source: wordnet30
• The state of being dissatisfied, unsatisfied, or discontented; uneasiness proceeding from the want of gratification, or from disappointed wishes and expectations.(noun)

  source: webster1913