From the NannyMUD documentation

LAST CHANGE

 2000-12-11 

TOPIC

 
NAME
          banish - Ensure separate name spaces for monsters and players


DESCRIPTION
  	This information is OBSOLETE.
	
	It is important that monsters are not created that have the same name
	as players. To avoid this, a directory /banish contains one file for
	every reserved monster name. To enter new names, go to adventurers
	guild, and do "banish name". If there already exists such a player,
	the command will fail.
  

  
NOTE
	This command is available in the wizsoul, too.