noun
Refers to a person who has moved into and occupies a dwelling, especially an apartment or a facility like a nursing home. Often used in real estate and housing contexts.
新しいマンションの入居者を募集しています。
We are looking for tenants for the new apartment building.
入居者同士のトラブルが増えている。
Troubles among residents are increasing.
借家人 is a legal/formal term for a tenant under a lease, emphasizing the rental contract. 入居者 is more general and can include occupants of owned units or facilities.
Compound of 入居 (にゅうきょ, 'moving in') + 者 (しゃ, 'person'). The meaning is transparent from its components.