Longman Dictionary of Contemporary English - critic

~1 n 1 someone whose job is to make judgments about the good and bad qualities of something, especially art, music, films etc  (The jazz critic for The Times panned the show, calling it `a joke'.) 2 someone who expresses strong disapproval or dislike of a person, idea, organization etc + of  (He became an outspoken critic of the country's educational policies.) 3 armchair critic someone who does nothing themselves but criticizes others for what they do