noun (n)

• a turning or tilting backward of an organ or body part(noun.state)

  Synonym:
  retroflexion, retroversion
  

  source: wordnet30
• an articulatory gesture made by turning the tip of the tongue back against the roof of the mouth(noun.communication)

  Synonym:
  retroflexion
  

  source: wordnet30
• the act of bending backward(noun.act)

  source: wordnet30