The word brittleness 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: 16
Highest Scoring Words With Friends™ Play In The Letters brittleness
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Seven Letter Word Alert: (63 words)
betitle, betters, bitsets, bitters, blesser, blister, bristle, brittle, enlists, entitle, entries, inserts, lenites, letters, listens, litters, nesters, nestles, netless, netters, nettles, rebites, reblent, rebless, relents, relines, relists, renests, resents, retests, retiles, retilts, retints, retitle, ribless, riblets, seitens, sestine, setters, settler, settles, silents, sinters, sitters, slitter, sterile, stilter, streets, telnets, tensest, tensile, tenters, tentier, tersest, testers, testier, tieless, tilters, tinsels, tinters, trebles, trestle, trienes