critic

Concise Oxford English Dictionary © 2008 Oxford University Press:
critic/ˈkrɪtɪk/

▶noun

• 1 a person who expresses an unfavourable opinion of something.

• 2 a person who judges the merits of literary or artistic works, especially one who does so professionally.

– origin C16: from L. criticus, from Gk kritikos, from kritēs ‘a judge’.