As a Noun: 1. A serious mental illness. People who suffer from it are unable to relate their thoughts and feelings to what is happening around them. It was once thought that such people had 'split' or 'multiple' personalities. English = schizophrenia. 2. A person who suffers from schizophrenia. English = schizophrenic. As a Verb or Adjective: 1. To relate to schizophrenia. English = (be) schizophrenic.