The word rottweilers 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: 15
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (46 words)
erotise, estriol, letters, litters, loiters, lorries, owliest, reliers, restore, reswore, retiles, retilts, retires, retitle, retorts, retries, retwist, rewires, rewrite, rewrote, rioters, roister, roselet, rosette, rotters, settler, slitter, sterile, stilter, swelter, swirler, teleost, testier, tilters, toilers, toilets, trestle, trowels, twirler, twister, wetters, witters, worries, wrester, wrestle, writers