The word devitalises 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: 17
Highest Scoring Words With Friends™ Play In The Letters devitalises
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Seven Letter Word Alert: (39 words)
advisee, advises, aediles, aidless, avidest, dailies, daisies, deities, delates, delists, desalts, desilts, details, devests, deviate, devisal, devises, diesels, dieties, dilates, disease, distils, divests, easiest, elative, estival, evilest, ilvaite, liaised, liaises, seaside, sedates, sidelit, sleaves, tealess, teasels, tieless, valeted, visited