noun (n)

• the elimination of fecal waste through the anus(noun.process)

  Synonym:
  defecation, shitting
  

  source: wordnet30
• the act of making something less tight(noun.act)

  Synonym:
  loosening
  Antonym:
  tightening
  

  source: wordnet30
• The act of loosening or slackening, or the state of being loosened or slackened.(noun)

  source: webster1913