The word octosyllable 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: 23
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (27 words)
acetyls, acolyte, alecost, ballets, ballots, beastly, caboose, callboy, callose, closely, cobalts, collate, coolest, cotylae, cotyles, coyotes, cytosol, lactose, locales, locally, locates, loosely, losable, lyocell, ocelots, oocytes, seaboot