Estrangement
Etymology
From the verb "estrange," which came through Old French from Latin extraneare, "to treat as a stranger," from extraneus, "foreign, external" (also the root of "strange"). The core idea is turning a familiar person into an outsider. The noun names the settled state of that turning-away, not just a single quarrel.
noun · /ih-STRAYNJ-munt/
The condition of having become distant or hostile toward someone you were once close to.
What it names
The specific rupture between people who used to be bound — family, friends, partners — who now behave toward each other like strangers.
Example
Years of estrangement ended awkwardly at the funeral, where the two brothers stood on opposite sides of the room.
Related idea
Alienation is a broad, often impersonal sense of being cut off from society or one’s work; estrangement is personal and pointed, aimed at a specific relationship that soured.