An Isaac Wunder order is an order issued by an Irish court restricting the ability of a vexatious litigant to institute legal proceedings without leave from that or another court, whether for a specified period of time or indefinitely.
It is named after Isaac Wunder, an Irishman who became notorious for instituting a number of actions that were subsequently deemed by the court to be frivolous or vexatious.
In the mid-1960s, the plaintiff in Keaveney v. Geraghty[1] sought damages for libel in proceedings before the High Court.
The defendant applied for a stay of proceedings on the grounds that they were, inter alia, frivolous and vexatious, and an abuse of process.
5) the court's inherent jurisdiction to make an order "where the court is satisfied that a person has habitually or persistently instituted vexatious or frivolous civil proceedings".