The word seismologists 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: 19
Highest Scoring Words With Friends™ Play In The Letters seismologists
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Seven Letter Word Alert: (31 words)
egoisms, egoists, egotism, elitism, elogist, glioses, gliosis, glosses, gooiest, goosies, iolites, loosest, meiosis, missile, mitoses, mitosis, molests, oiliest, oligist, oolites, osmosis, semilog, similes, sissies, soloist, somites, stimies, stogies, stomies, stooges, stoolie