Someone who pays for a place to sleep, and usually for meals, in someone else’s house. (Cambridge Dictionary)
A person who lives in rented quarters in another’s house; roomer. (Dictionary.com)
A lodger is a person who pays money to live in someone else’s house. (Collins Dictionary)
A person who rents accommodation in another person’s house. (Oxford Dictionary)
Lodgers vs tenants: how your rights and responsibilities change.
What’s the difference between a tenant and a lodger?