The word semideserts 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: 15
Highest Scoring Words With Friends™ Play In The Letters semideserts
:
Seven Letter Word Alert: (43 words)
demerit, demises, demists, deserts, desires, desists, dessert, diester, dieters, dimeter, dresses, eeriest, emersed, emerses, esteems, meeters, merited, messier, metered, metrise, misters, mitered, redeems, reedits, reemits, reested, remeets, reseeds, resides, resists, restems, retimed, retimes, seeders, seedier, sisters, smiters, steered, strides, teemers, tressed, tresses, tridems