A more thorough explanation:

Selective prospectivity is a legal term that refers to a court's decision to apply a new rule of law in a specific case, but to apply the old rule in all other cases that were pending at the time the new rule was announced or in which the facts predate the new rule's announcement.

For example, let's say that a court announces a new rule that makes it illegal to use a certain type of pesticide. If a case comes before the court that involves the use of that pesticide after the new rule was announced, the court will apply the new rule. However, if there are other cases pending that involve the use of the same pesticide before the new rule was announced, the court will apply the old rule.

Another example could be a court ruling that a certain type of contract is unenforceable. If a case comes before the court that involves that type of contract after the ruling, the court will apply the new rule. However, if there are other cases pending that involve the same type of contract before the ruling, the court will apply the old rule.

These examples illustrate how selective prospectivity works in practice. It allows courts to apply new rules of law in a fair and consistent manner, while also respecting the rights of parties who were subject to the old rule before the new rule was announced.