Misomaniac is a word that refers to an individual who hates humanity. However, there are also other words and phrases that can be used to describe this type of person. Some possible synonyms include misanthrope, negativist, pessimist, cynic, and grump. A misanthrope is someone who has a general dislike or distrust of other people. A negativist is someone who always sees the negative in situations. A pessimist is someone who always expects the worst outcome. A cynic is someone who distrusts other people's motives and actions. A grump is someone who is constantly ill-tempered and easily irritated. All of these words can be used interchangeably with the term misomaniac, depending on the context.