What does estoppel mean in legal terms?

Estoppel refers to a legal principle that prevents an individual from asserting something contrary to what is implied by a previous action or statement. This is rooted in the idea of fairness and consistency; when one party has made a representation or taken a particular position, and someone else has relied on that to their detriment, the first party may be barred from changing their stance.

In practice, estoppel can come into play in various legal scenarios, including contract disputes and property law. For example, if a landlord communicates a certain policy regarding a lease, and a tenant relies on this to make decisions (like investing in property improvements), the landlord may be estopped from suddenly changing the policy to the tenant's disadvantage. This provides protection for individuals who rely on others' representations or conduct, creating an expectation that they can act upon those assurances.

The other options do not align with this concept. Rescinding a contract based on financial terms pertains to contract law but does not capture the broader idea of preventing claims based on prior behavior. Establishing legal agency usually involves formal agreements and documentation, rather than the implications of past conduct. Evaluating agency performance is unrelated to the core idea of estoppel, which focuses on the implications of one's actions or statements in legal contexts