The word promptitude is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 22
Highest Scoring Words With Friends™ Plays In The Letters promptitude
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Seven Letter Word Alert: (25 words)
diopter, dioptre, dottier, dumpier, imputed, ioduret, omitted, omitter, outpipe, outride, peridot, poutier, primped, puttied, puttier, timeout, tiptoed, tiptoer, tripped, trouped, trumped, trumpet, tutored, umpired, uptempo