A more thorough explanation:

Indispensable party

An indispensable party is a person or entity that must be included in a lawsuit because their rights will be affected by the final judgment. If they are not included, the court cannot make a final decision.

If someone sues their neighbors to force them to cut down a tree that is a danger to their house, all owners of the property where the tree is located must be included in the lawsuit. This is because the owners' rights will be affected by the final decision. Another example is if a company is suing another company for breach of contract, any third party that was involved in the contract must be included in the lawsuit.

These examples illustrate that an indispensable party is someone who has a direct interest in the outcome of a lawsuit. If they are not included, the court cannot make a final decision that will be fair to all parties involved.