A more thorough explanation:

A quasi-tenant is a sublessee that the new tenant or reversioner allows to hold over. This means that the sublessee is allowed to stay in the property even after the original lease has expired.

For example, if John leases an apartment from Jane for a year and then decides to move out before the lease is up, he may sublease the apartment to Sarah for the remaining months. Sarah would be considered a quasi-tenant because she is not the original tenant, but is allowed to stay in the apartment by the new tenant or reversioner (Jane).

Another example of a quasi-tenant is a holdover tenant. This is a person who remains in possession of real property after a previous tenancy (especially one under a lease) expires, thus giving rise to a tenancy at sufferance. The holdover tenant is allowed to stay in the property by the new tenant or reversioner.