Definition– unlawful detainer refers to the unjustifiable retention or keeping possession of real property by one whose original entry or possession was lawful.
What It Really Means
Unlawful detainer occurs when a tenant, who was allowed to be in possession of a property, maintains possession of that property past the time period in which they were allowed to.
Terry is renting an apartment from Luisa for a period of one year, to begin on November 1, 2000 and to end on October 31, 2001. On November 2, 2001, Louisa goes by the apartment to clean and prepare the apartment for a new tenant, but sees that Terry is still living at the apartment.