The word undersellers 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 undersellers
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Seven Letter Word Alert: (32 words)
dresser, duelers, dueller, eldress, eluders, endless, endures, ensured, ensurer, ensures, lenders, needers, needler, needles, nursers, redness, redress, reelers, renders, reseeds, resells, resends, seeders, sellers, senders, serener, slender, slurred, sneered, sneerer, undress, unreels