Estoppel:

Estoppel is a legal doctrine that prevents a person from asserting a claim or defence that is contrary to what they have previously stated, agreed upon, or established by their conduct. It is based on principles of fairness and preventing injustice by holding individuals to their word or actions. Estoppel can arise from various situations, such as promises, representations, or silence, and it aims to prevent parties from changing their position to the detriment of others. In essence, estoppel serves to maintain consistency and integrity in legal dealings and interactions.

Let's say you promise your friend you'll give them your old bike. Later, you change your mind and say you never promised them anything. But because your friend relied on your promise and got excited about getting the bike, you can't take it back. That's estoppel. Another example is if you let someone use your garden for years without saying anything. Then, suddenly, you say they can't use it anymore. Since they relied on your silence and spent time and money on the garden, you can't change your mind. That's estoppel too. So, estoppel is about sticking to your word, even if you didn't say anything directly.

Res Judicata:

Res judicata, Latin for "a thing adjudicated," is a legal principle that prevents the same case from being relitigated between the same parties once it has been decided by a court with jurisdiction. In simple terms, it means that once a court has made a final decision on a legal matter, that decision is binding and cannot be challenged in subsequent legal proceedings. Res judicata aims to promote finality and judicial efficiency by preventing parties from endlessly litigating the same issues.

Res judicata is like when you've played a game and the game is over. You can't keep playing the same game again and again. In legal terms, it means if a court has already made a decision about something, you can't keep bringing the same issue to court over and over.

For example, let's say you sue your neighbour because their tree fell on your fence and damaged it. The court decides your neighbour has to pay for the damage. That's the end of it. You can't sue your neighbour again for the same tree falling on your fence.

Another example is if you get into a car accident, and the court decides the other driver was at fault and has to pay you damages. You can't then go to court again and sue the same driver for the same accident.

So, res judicata means once a court has decided something, that's the final decision, and you can't keep bringing the same issue back to court.

Differences between Estoppel and Res Judicata:

The differences between Estoppel and Res Judicata are given below:

1. Estoppel deals with evidence, while Res Judicata deals with legal procedures.
2. Estoppel prevents a person from saying one thing at one time and retreating from it another time. Res judicata stops another court from hearing the same case between the same parties if it has already been decided by a competent court.
3. In the case of estoppel, it is the person who is estopped, whereas in the case of res judicata it is the court that ceases to have jurisdiction.
4. Estoppel shuts the mouth of a person and prevents him from making contradictory statements, whereas res judicata ousts the jurisdiction of the court and prevents it from deciding over again a matter already decided upon by a competent court.
5. Estoppel arises from the actions of the involved parties, whereas Res Judicata stems from the court's decision.
6. Estoppel is often used in contractual disputes, real estate transactions, and other civil matters. Res Judicata is used in civil litigation to prevent repetitive lawsuits.
7. Estoppel can arise at any stage of legal proceedings or even before litigation begins. Res Judicata applies after a final judgment has been issued by a court.
8. Estoppel can be either equitable or legal, depending on the circumstances. Res Judicata is a legal principle.
9. Estoppel prevents someone from asserting a fact or claim that contradicts what they previously stated or agreed upon. Res Judicata means "a thing decided" and refers to the legal doctrine that a matter that has been adjudicated by a competent court cannot be pursued further by the same parties.
10. Estoppel can be used for both facts and laws. Res Judicata usually deals with the same legal issues or claims that were already settled.
11. Estoppel typically involves two parties, where one party is estopped from taking a certain position against the other. Res Judicata means the same parties or their close connections can't reopen a legal issue that's already been settled.
12. The remedy for estoppel may include preventing a party from asserting a particular claim or defence. In res Judicata the remedy is the finality of the judgment, preventing further litigation on the same matter.
13. Estoppel focuses on preventing inconsistency in a party's position, while res judicata aims to prevent repetitive litigation by enforcing finality on legal matters.
14. Estoppel is based on rule of equity, justice and good consciences. Res judicata is based on public policy.
15. Sections 115 to 117 of the Indian Evidence Act, 1872 incorporate the principle of Estoppel. The rule regarding res judicata is laid down under section 11 of the Civil Procedure Code,1908.
16. Estoppel can be inferred from the conduct of the parties. Res judicata is claimed on basis of previous decision of competent court.
17. The doctrine of estoppel is a legal concept that prohibits a person from making a claim or asserting a right that contradicts their previous statements or agreements, especially if it would harm someone who relied on those statements or actions. On the other hand, res judicata is a legal principle that prevents the same parties from litigating an issue that has already been decided by a court. It is a doctrine that prohibits the same matter from being re-litigated between the same parties, based on a final judgment made by a court.
18. Estoppel is applicable to both individuals and entities, effectively prohibiting them from making assertions or exercising rights that are inconsistent with their previous statements or conduct.

Conversely, res judicata primarily pertains to legal proceedings and the power of court judgments, preventing the involved parties from rehashing previously settled matters.