The word rebelliousness 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: 21
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (72 words)
beeline, bellies, blesser, blesses, blisses, blouses, boilers, boluses, bonuses, boreens, bossier, bousier, bruises, bullies, bullion, ebonies, elusion, enbuses, enrobes, enrolls, ensouls, ensures, illness, insoles, insures, issuers, leisure, lesions, lessees, lessens, lessons, lessors, libeler, lioness, lobules, lossier, lousier, osseins, rebells, rebills, rebless, reboils, reissue, relines, resells, resnubs, resoils, resoles, ribless, riboses, sellers, seniors, sensors, serious, sessile, session, sinless, sinuses, soirees, soluble, sonless, suberin, subsoil, sullies, sunless, sunrise, unbless, unilobe, unreels, unrobes, unrolls, useless