The word infeasibility 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: 23
Highest Scoring Words With Friends™ Play In The Letters infeasibility
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Seven Letter Word Alert: (30 words)
ability, albites, alibies, astilbe, beastly, beatify, belfast, bylines, elastin, entails, faintly, falsity, fanbelt, filiate, finales, finials, flybane, ileitis, inflate, initial, instyle, lesbian, libates, nailset, nastily, niftily, saintly, salient, tailfin, tenably