The word malacologists 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: 23
Highest Scoring Words With Friends™ Play In The Letters malacologists
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Seven Letter Word Alert: (26 words)
atomics, catalog, coastal, colossi, galoots, glacial, gliomas, logical, magical, mascots, miscall, miscast, mosaics, osmotic, salamis, scatoma, scillas, scotoma, sitcoms, slaloms, socials, soloist, somatic, stalags, stigmas, stoical