The word dessiatine 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™ Plays In The Letters
Seven Letter Word Alert: (28 words)
aniseed, daisies, deities, densest, destain, destine, detains, dieties, dietine, disease, dissent, easiest, indites, insides, instead, sainted, sateens, seaside, sedates, seitans, seitens, senates, sensate, sestina, sestine, snidest, stained, standee