The word trustingness 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: 17
Highest Scoring Words With Friends™ Plays In The Letters trustingness
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Seven Letter Word Alert: (67 words)
ensigns, ensuing, entrust, gunners, gunters, gussets, gussies, gustier, gutsier, gutters, ingests, ingress, inserts, insures, intents, interns, intrust, inturns, issuers, nesting, netting, nursing, nutsier, nutters, nuttier, nutting, renting, resigns, resists, resting, retints, reusing, russets, rusting, rutting, sensing, setting, signers, signets, singers, sinners, sinters, sinuses, sisters, sitters, stinger, strings, stunner, stunter, suiters, sunnier, sunnies, sunrise, sunsets, tensing, tenting, testing, tigress, tinners, tinters, tissues, trusses, tunings, turning, uniters, unrests, unrisen