A more thorough explanation:

An at-will tenancy is a type of lease agreement where the tenant occupies the property with the landlord's consent but without any fixed terms, such as duration or rent. This means that either the tenant or the landlord can terminate the tenancy at any time with fair notice.

For example, if a landlord allows a friend to stay in their spare room without any written agreement, this would be considered an at-will tenancy. The friend can leave at any time, and the landlord can ask them to leave with fair notice.

At-will tenancy is different from other types of tenancy, such as a periodic tenancy, which automatically renews for successive periods, or a tenancy for a term, which has a fixed duration.