unsetopt [ {+|-}options | {+|-}o option_name ] [ name ... ]
       Unset the options for the shell.  All options specified either  with
       flags or by name are unset.  If no arguments are supplied, the names
       of all options currently unset are printed.  If the -m flag is given
       the  arguments are taken as patterns (which should be quoted to pre-
       serve them from being interpreted as glob patterns), and all options
       with names matching these patterns are unset.
