Webster's Revised Unabridged Dictionary · 1913

Imprescriptible

Imprescriptible , adjective

[Prefix im- not + prescriptible: compare French imprescriptible.]

1.
Not capable of being lost or impaired by neglect, by disuse, or by the claims of another founded on prescription; -- of rights.
The right of navigation, fishing, and others that may be exercised on the sea, belonging to the right of mere ability, are imprescriptible. — Vattel (Trans. )
2.
Not derived from, or dependent on, external authority; self-evidencing; obvious.
The imprescriptible laws of the pure reason. — Colerridge