The word marbleises 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: 17
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (44 words)
abseils, aimless, airless, amblers, ambries, armless, balmier, bemires, beslime, besmear, blamers, blesser, braises, braless, earless, embases, leasers, limbers, mailers, marbles, mealier, measles, messier, rambles, realise, realism, rebales, rebases, reblame, rebless, remails, resails, resales, reseals, ribless, rimless, sailers, sealers, seamers, seamier, serials, seriema, siamese, smilers