The word coarsening 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
Seven Letter Word Alert: (45 words)
agnosic, agonies, agonise, arcsine, arsenic, canines, cannier, canoers, cargoes, carnies, ceasing, coarsen, cognise, coinage, coiners, consign, coreign, corneas, corning, corsage, craning, cringes, cronies, earning, erasing, gainers, ignores, insaner, ironage, nearing, oranges, organic, recoins, regains, regions, roaning, scanner, scaring, scoriae, scoring, searing, signora, snaring, snoring, soaring