help mutter

Usage: mutter <player> <text>
       m <player> <text>

The `mutter' command, abbreviable to `m', lets you say things `behind someone's
back', so that everyone present except for that person hears what you say.  For
instance, if poslfit types `mutter steven It's in the FAQ!', everyone except
Steven will see `poslfit mutters behind Steven's back: "It's in the FAQ!"'.
Since this command would otherwise lend itself to unfriendly abuse, it is
designed to fail every now and then.  In the above example, everyone in the
room, including Steven, would hear `poslfit mutters a little too loudly behind
Steven's back: "It's in the FAQ!"'.

See also: talk2