kill and its cross-references

kill

kill <nick> [<reason>]
 Asks me to throw that client off IRC completely, using my IRC
 Operator privilege.  You must have identified yourself as the user
 to whom the nick is registered.  (See `help register'.)

register

register            register your nick (or make it secure)
register delete     delete your nick registration
register insecure   register your nick insecurely
 I only store settings for registered nicks.  For `insecure' nicks
 anyone who currently holds that nick can change its settings (see
 `help set', including securing it to their username.  `secure'
 nicks can only have their settings changed by the user to which they
 are registered, after identifying themselves (see `help identify').