The word estivating 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™ Play In The Letters estivating
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Seven Letter Word Alert: (24 words)
eviting, ignites, instate, invites, naivest, natives, seating, setting, sieving, sitting, stating, stative, staving, stiving, tasting, teasing, testing, tiniest, vainest, vatting, vesting, vetting, vintage, vitiate