Fanaticalness is a strong and intense form of devotion or dedication to something or someone. Synonyms of this word include zealotry, extremism, obsession, fervor, and fanaticism. These words all refer to an extreme and often irrational enthusiasm or passion for a particular cause or belief. Other synonyms for fanaticalness might include single-mindedness, infatuation, mania, fixation, or ardor. While these words may have slightly different connotations, they all point to an unyielding and unwavering commitment to a particular ideal or goal. Whether positive or negative, fanaticalness can often be a powerful driving force behind great achievements or dangerous and destructive behavior.