Quiz: Remember the definition of mal de mer?
"inalienable, not subject to prescription," 1560s, French imprescriptible (16c.) or a native formation from assimilated form of in- (1) "not, opposite of" + Latin praescriptus, past participle of praescribere "to write beforehand" (see prescribe). Usually with right. Alternative imprescribable is attested from 1887.