Unlawful detention in the real property context means keeping possession of real property without a right, such as after a lease has expired. Such possession entitles the owner to file a lawsuit for "unlawful detainer," asking for possession by court order, unpaid rent and damages.
This form is a generic example that may be referred to when preparing such a form for your particular state. It is for illustrative purposes only. Local laws should be consulted to determine any specific requirements for such a form in a particular jurisdiction.