What is the psychological term for someone who hates everything?

The psychological term for someone who hates everything is misanthropy. Misanthropy is a general dislike or hatred of humanity or human nature. It can be expressed in a number of ways, from simple grumbling about people to active hatred and hostility. Misanthropes may believe that humans are inherently evil or corrupt, or they may simply find them to be annoying and untrustworthy. In some cases, misanthropy may be a symptom of clinical depression or other mental health problems.