The word incapacities 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™ Play In The Letters incapacities
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Seven Letter Word Alert: (33 words)
accents, accepts, accites, actinic, anapest, anaptic, ascetic, aseptic, canapes, capstan, captain, catnaps, catnips, icecaps, incites, inscape, inspect, panties, patinae, patinas, patines, peasant, peccant, pectins, pianist, picante, picnics, saccate, satanic, sceptic, sciatic, spicate, tiepins