The word granduncles 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: 21
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (56 words)
anglers, asunder, candler, candles, clanged, cradles, crusade, cudgels, curdles, dancers, dangers, dangler, dangles, desugar, enlards, ensnarl, ganders, gardens, glanced, glancer, glances, glucans, gnarled, granule, guldens, gunners, lancers, landers, langurs, launder, nuanced, nuances, nuclear, reclads, reclang, recusal, runnels, scanned, scanner, secular, slander, slanged, snarled, sugared, uncaged, uncages, uncared, uncased, unclads, unclean, unclear, unlaced, unlaces, unladen, unlearn, unsnarl