When something that was once publically listed in some form as currently active and available (such as a site URL) but no longer given in the same current public list today but still remains currently active and available as it was originally created. For it is now excluded from the current list and censored for whatever reason.
Applying this true formed definition forward also includes anything that is newly created which was never before listed but is excluded from listing under the same censored (consideration) policy.
True English forms: de-list de-listed
Even if adult oriented materials are flagged and desired, these current active Yahoo groups are not provided in search results of the available Yahoo groups search -- when they used to be and now are delisted.
Several "user supported" off-site listings of these active Yahoo groups with the correct URLs for the group home page and subscription email addresses of course followed.
History: "Yahoo Groups" took over "egroups" which took over "onelist".
No longer single listed, huh? It now has delisted groups from once was the onelist concept.
Delisting does not only apply to Yahoo Groups specifically...