The word cabdrivers 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: 21
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (39 words)
abiders, adverbs, advices, adviser, airbeds, arrived, arrives, ascribe, birders, bracers, braider, braised, braiser, brasier, carbide, carders, carried, carries, carvers, cervids, crabier, cravers, decarbs, drivers, rabider, radices, raiders, rebraid, scabrid, scarier, scarred, scribed, scriber, seabird, sidebar, sidecar, varices, viscera, vraiced