Definitions

1. noun

a lease granted by a tenant to another person, often in contravention of the original lease agreement

“The landlord was not aware that the tenant had entered into an underlease with another party.”

2. verb

to lease or let land or a building to another person, especially in a way that is contrary to the terms of the original lease

“The tenant decided to underlease the property to a group of students without the landlord’s permission.”