noun (n)

• the quality of being toward the back or toward the rear end(noun.attribute)

  Antonym:
  anteriority
  

  source: wordnet30
• following in time(noun.attribute)

  Synonym:
  subsequence, subsequentness
  Antonym:
  antecedence, antecedency, anteriority, precedence, precedency, priority
  

  source: wordnet30
• The state of being later or subsequent; as, posteriority of time, or of an event; -- opposed to priority.(noun)

  source: webster1913