The word driveshaft 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: 20
Highest Scoring Words With Friends™ Play In The Letters driveshaft
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Seven Letter Word Alert: (33 words)
adverts, adviser, aridest, astride, avidest, dearths, dervish, disrate, dithers, diverts, fairest, fathers, hafters, hardest, harvest, hastier, hatreds, ratfish, redfish, reshift, shadier, shafted, shifted, shifter, shirted, starved, strived, threads, thrived, thrives, tirades, trashed, veritas