person living with a family; lodger
Refers to someone who lives in the same household as a family, often implying a non-family member such as a lodger or boarder.
He lived with the family as a lodger for three years.
housemate; flatmate; roommate
General term for someone who shares a living space, such as a housemate, flatmate, or roommate.
I'm looking for a new housemate.
Compound of 同居 (どうきょ, 'living together') + 人 (にん, 'person').