Rival : a person or thing competing with another for the same objective or for superiority in the same field of activity.Enthusiast : a person who is very interested in a particular activity or subject.Critic : a person who expresses an unfavourable opinion of something.Indifferent : having no particular interest or sympathy; unconcerned.Aficionado : a person who is very knowledgeable and enthusiastic about an activity, subject, or pastime.Synonym of Aficionado is Enthusiast