U1N1M3I1S1T1A1K5A1B3L1E1
20 points
UNMISTAKABLE is validvalid
not mistakable [adj] : UNMISTAKABLY [adv]
not capable of being mistaken or misunderstood, also UNMISTAKEABLE [adj UNMISTAKABLY]
not mistakable [adj] : UNMISTAKABLY [adv]
not capable of being mistaken or misunderstood, also UNMISTAKEABLE [adj UNMISTAKABLY]