A constructive eviction is when a landlord takes action against a tenant in such an extreme manner that it interferes with the tenant's right to live at the property. If a landlord causes a constructive eviction, the landlord may lose his right to bring a legal eviction proceeding.
Examples of this would include changing the locks, interfering with or shutting off utilities, or extreme harassment of the tenant with noise or other things that make it difficult for the tenant to live at the property. if a tenant can prove these things, then the court may find that a constructive eviction has taken place, and the landlord can be denied a judgment of possession and a warrant of eviction because of the behavior that led to the finding of a constructive eviction.