Lease dictionary
Tenancy at will
An informal tenancy with no lease term at all - either side can end it with minimal formality.
A tenancy at will exists when someone rents with no fixed term and often no written lease - by handshake, or after a lease expires and rent keeps changing hands informally. It's legal, but everything rests on state default rules.
Despite the name, most states still require proper written notice to end it - you're not removable on a whim, and habitability and anti-retaliation protections still apply in full.
Watch out
No written lease doesn't mean no rights. It means state defaults fill every gap - so knowing your state's rules matters twice as much.
See it in action
The Tenant rights by state puts this term to work for you.