I1M3P3A1S1S1A1B3L1E1
16 points
IMPASSABLE is validvalid
not passable [adj] : IMPASSABILITY [n], IMPASSABLENESS [n], IMPASSABLY [adv]
that cannot be passed [adj IMPASSABLY]
not passable [adj] : IMPASSABILITY [n], IMPASSABLENESS [n], IMPASSABLY [adv]
that cannot be passed [adj IMPASSABLY]