A person who unfairly criticizes or damages the reputation of someone or something.
From denigrate + -or (agent suffix). The suffix -or comes from Latin and creates a noun for 'one who does' the action of the root verb.
Every language seems to have words that turn verbs into people who do those actions—it's how we create job titles and roles, from 'teacher' to 'denigrator,' even for negative behaviors.
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