Thayer's Greek Lexicon

 1. to draw back, let down, lower
  1) to withdraw: of a timid person
2. to withdraw one's self, i.e. to be timid, to cover, shrink
  1) of those who from timidity hesitate to avow what they believe
  2) to be unwilling to utter from fear
  3) to shrink from declaring, to conceal, dissemble