self-will /-ˈwɪl/
  任性,固執
  Self-will n.  One's own will, esp. when opposed to that of others; obstinacy.
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  self-will
       n 1: resolute adherence to your own ideas or desires [syn: stubbornness,
             bullheadedness, obstinacy, obstinance, pigheadedness]
       2: the trait of resolutely controlling your own behavior [syn:
          self-control, self-possession, possession, willpower,
           self-command]