A hysterical person is someone who is overly emotional and often uncontrollably laughing or crying. The term 'hysterical person' can be broken down into two crossword solutions: RIOT (4 letters) and MEEMIE (6 letters). RIOT is defined as a violent disturbance of the peace by a crowd, while MEEMIE is an informal term for someone who is silly or foolish. Together, these two words describe someone who is overly emotional and often uncontrollably laughing or crying.