UNP'ASSABLE, adjective 1. Not admitting persons to pass; impassable; as unpassable roads, rivers or mountains. [Impassable is more generally used.] 2. Not current; not received in common payments; as unpassable notes or coins. [Instead of this, uncurrent and not current are now used.]
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI