Post-termination restrictions are sometimes also known as restrictive covenants. They prevent you from carrying out certain activities once you have left your employer. They are typically imposed on senior employees and those with access to sensitive information or relationships and are designed to protect the interests of the business.
Post-termination restrictions can be a legal minefield. Unless carefully drafted, they may not be legally binding. Likewise, over-zealous employers can find that restrictions that go too far are not upheld in court.
Speak to an experienced employment solicitor if you are unhappy about the restraints placed on you post-termination.