The word labyrinthitis 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: 22
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (29 words)
ability, absinth, bairnly, biliary, brashly, bristly, hastily, inhabit, inhibit, initial, nastily, nattily, nitryls, rattish, saintly, shinily, starlit, straint, tarnish, tartish, tastily, thirsty, thistly, transit, tribals, trinity, trysail, tyrants, yttrias