A detractor is someone who speaks negatively about a person, idea, or thing. A NONBELIEVER is someone who does not accept a particular belief or doctrine. A CYNIC is someone who believes that people are motivated by self-interest and distrusts the motives of others. A CRITIC is someone who evaluates or judges something. An ANTI is someone who is opposed to a particular idea or thing. A nast is someone who is unpleasant or rude. A KNOCKER is someone who disparages or belittles something. A TORY is someone who holds conservative political views. A whig is someone who holds liberal political views. A PESSIMIST is someone who expects the worst possible outcome. All of these terms can be used to describe a detractor, as they all refer to someone who speaks negatively about something.