reply

COMMAND

reply <message>
  
  If someone told you something, you can use reply to tell him back without
  giving the name of the recipient. For tell-rings, i.e. if someone told to
  more than one person including you, your reply is told to all of them.
  This command does the same as 'tell back <message>'.

See also:
  away, say, mudlink, echomode, ignore, rwho, rpeers, tell