The word polymerizing 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: 33
Highest Scoring Words With Friends™ Play In The Letters polymerizing
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Seven Letter Word Alert: (34 words)
eloping, ergonym, gimpier, gremlin, grimily, imperil, impinge, implore, ionizer, limping, lionize, liriope, mingler, mongery, mongrel, perming, pilgrim, pingler, polymer, preying, priming, prizing, progeny, proline, pronely, relying, roiling, romping, yelming, yelping, zeroing, zingier, zipline, zymogen