The word rheological 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: 20
Highest Scoring Words With Friends™ Play In The Letters rheological
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Seven Letter Word Alert: (24 words)
aircell, aircool, airhole, alcogel, alcohol, allegro, calorie, chiller, chloral, cholera, choragi, chorale, choregi, coalier, collage, collier, corolla, glacier, gorilla, gracile, helical, logical, ocellar, rechill