The word unperceiving 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: 27
Highest Scoring Words With Friends™ Play In The Letters unperceiving
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Seven Letter Word Alert: (26 words)
cuprene, curving, epicure, eugenic, eupneic, evening, generic, genuine, incurve, inuring, nerving, peering, peeving, penguin, piecing, pricing, pruning, punnier, reeving, reicing, reining, ruining, unnerve, veering, veinier, veining