The word grandnieces 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: 19
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (80 words)
adenine, angered, aniseed, arcsine, arsenic, cairned, candies, canines, cannier, carding, careens, carnies, ceasing, cinders, craning, creased, cringed, cringes, dancers, dancing, dangers, darning, dearies, decanes, decares, decries, deicers, deniers, deraign, derange, dinners, discern, earning, encased, endears, endings, engined, engines, enraged, enrages, ensnare, erasing, gainers, ganders, gardens, genders, generic, grained, greased, greisen, grenade, grinned, incased, incense, innards, insaner, nearing, needing, radices, readies, reading, recaned, recanes, regains, reigned, rending, rescind, sandier, sanding, sardine, scanned, scanner, scaring, searing, sedgier, seeding, sending, sidecar, sincere, snaring