The word whippletrees 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: 24
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (64 words)
eeriest, epistle, helpers, hippest, peelers, peepers, pelites, pelters, peptise, perlite, petrels, pewters, philter, philtre, reheels, repeels, repiles, repipes, replete, replies, reptile, respelt, respite, resplit, resweep, reswept, retiles, rewipes, ripples, ripplet, seepier, seether, sheeter, shelter, shipper, sleeper, slipper, slither, spewier, steelie, steeper, steeple, stepper, sterile, stipple, sweeper, sweeter, sweetie, swelter, tippers, tippler, tipples, triples, weepers, weepier, wheeler, wheelie, whipper, whippet, whisper, whistle, withers, wrestle, writhes