The word flustering 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: 18
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (55 words)
eluting, engulfs, felting, figures, filters, fingers, fistule, fluents, fluster, fluters, fluting, fringes, fueling, furling, girnels, glisten, glister, gluiest, glutens, gristle, gruntle, gunfire, gunters, gustier, gutsier, infuser, lifters, lingers, luniest, lustier, lusting, nutsier, restful, resting, reusing, ringlet, rulings, rusting, rutiles, singlet, slinger, snifter, stifler, stinger, sulfite, surfeit, surfing, tinfuls, tingler, tingles, trifles, turfing, ugliest, uniters, utensil