U1N1T1H4I1N1K5A1B3L1E1
20 points
UNTHINKABLE is validvalid
not thinkable [adj] : UNTHINKABILITY [n], UNTHINKABLY [adv]
that cannot be thought [adj UNTHINKABLY]
not thinkable [adj] : UNTHINKABILITY [n], UNTHINKABLY [adv]
that cannot be thought [adj UNTHINKABLY]