The word desiderata 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: 12
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (34 words)
aerated, aerates, aeriest, airdate, aridest, astride, atresia, dastard, deadest, deaired, dearest, dearies, derides, desired, diester, dieters, disrate, radiate, readied, readies, reasted, redated, redates, reddest, reedits, resided, sedated, sedater, seriate, tasered, teddies, tiaraed, tirades, treaded