Inmate
来自Big Physics
late 16th century (denoting a person who shared a house, specifically a lodger or subtenant): probably originally from inn + mate1, later associated with in.
wiktionary
From inn + mate, or from in- + mate.
etymonline
inmate (n.)
1580s, "one allowed to live in a house rented by another" (usually for a consideration), from in (adj.) "inside" + mate (n.) "companion." OED suggests the first element is perhaps originally inn. Sense of "one confined to an institution" is first attested 1834.
