The crossword solution for the term 'Maniac Prefix' is 'EGO', which is a three-letter word. EGO is a Latin word that means 'I' or 'SELF'. It is often used to refer to a person's sense of SELF-importance or SELF-esteem. In psychology, it is used to refer to the part of the personality that is conscious and aware of one's own identity and behavior. In psychiatry, it is used to describe a mental disorder characterized by extreme excitement, delusions, and irrational behavior.