ret·ro·flex /ˈrɛtrəˌflɛks/
  (a.)反曲的;翻轉的
  Re·tro·flex Re·tro·flexed a.  Reflexed; bent or turned abruptly backward.
  ◄ ►
  retroflex
       adj 1: bent or curved backward [syn: retroflexed]
       2: pronounced with the tip of the tongue turned back toward the
          hard palate [syn: cacuminal]
       v 1: bend or turn backward [syn: replicate]
       2: articulate (a consonant) with the tongue curled back against
          the palate; "Indian accents can be characterized by the
          fact that speakers retroflex their consonants"