Source : Webster's Revised Unabridged Dictionary (1913)

Self-will \Self`-will"\, n. [AS. selfwill.]
   One's own will, esp. when opposed to that of others;
   obstinacy.

Source : WordNet®

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}]