The word microorganism 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: 25
Highest Scoring Words With Friends™ Play In The Letters microorganism
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Seven Letter Word Alert: (45 words)
agnosic, agonism, airings, ammonic, animism, arising, carrion, comings, commons, coronas, corsair, crimson, iconism, incisor, isogram, maiming, marconi, margins, maroons, marring, masonic, miasmic, microns, minicam, minimas, miscoin, mooring, moronic, nicosia, omicron, organic, origami, origins, racoons, raising, ramming, rancors, rimming, roaming, roaring, rooming, scaring, scoring, signora, soaring