The word allusiveness 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 allusiveness
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Seven Letter Word Alert: (29 words)
avenues, elusive, eluvial, enseals, enslave, evulses, illness, inulase, lassies, leavens, lessens, salines, sensual, sessile, silanes, silvans, sinless, sinuses, sleaves, snivels, sullies, sunless, unseals, unveils, useless, veinule, venules, vessels, visuals