Contract Glossary

Estoppel

Definition

A legal principle that prevents someone from going back on their word when another person reasonably relied on that word and would be harmed by the reversal. In plain English: if you said it, acted on it, and someone trusted you, you can't take it back.

In Practice

Estoppel comes up when there's no formal contract but someone made a promise you relied on. Say a landlord tells you verbally that your rent won't increase, so you invest $10,000 renovating the space. Under promissory estoppel, a court might hold the landlord to that promise even without a written agreement.