The Jargon File (version 4.4.7, 29 Dec 2003):

link-dead
 adj.

    [MUD] The state a player is in when they kill their connection to a MUD
    without leaving it properly. The player is then commonly left as a statue
    in the game, and is only removed after a certain period of time (an hour on
    most MUDs). Used on IRC as well, although it is inappropriate in that
    context. Compare netdead.


The Free On-line Dictionary of Computing (30 December 2018):

link-dead

   Said of a MUD character who has frozen in place because of a
   dropped network connection.

   [Jargon File]

   (1995-01-24)