What legal concept prevents an insurer from denying a claim after waiving a provision?

The concept that prevents an insurer from denying a claim after waiving a provision is best described by the term "waiver and estoppel." When an insurer voluntarily relinquishes a known right (waiver), such as the right to deny a claim based on a certain provision in the insurance policy, they may be prevented from later asserting that right through the doctrine of estoppel. This means that the insurer cannot go back on their word or previous actions if the policyholder has relied on that waiver to their detriment.

Waiver refers to the insurer's intentional decision to forgo enforcing a particular provision, which, when combined with estoppel, establishes that the insurer must honor that decision. Estoppel provides a legal mechanism ensuring that a party cannot assert something contrary to what is implied by a previous act, claim, or statement when someone else has reasonably relied on that implication.

This combination of waiver and estoppel serves to protect policyholders by holding insurers accountable for their actions and communications, creating a more reliable and fair claims process.